Editing Plaid Cymru (section)

==History==
{{Main|History of Plaid Cymru}}

===Beginnings===
[[File:Penblwydd Plaid Cymru Anniversary - geograph.org.uk - 644944.jpg|thumb|Plaque commemorating the founding of {{lang|cy|Plaid Cymru, [[Pwllheli]]|italic=no}}]]
While both the [[Labour Party (UK)|Labour]] and [[Liberal Party (UK)|Liberal]] parties of the early 20th century had accommodated demands for Welsh home rule, no political party existed for the purpose of establishing a Welsh government. {{langnf|cy|Plaid Genedlaethol Cymru|the National Party of Wales}} was formed on 5 August 1925, by [[Moses Gruffydd]], [[H. R. Jones]] and [[Lewis Valentine]], members of {{langnf|cy|Byddin Ymreolwyr Cymru|the Home Rule Army of Wales|paren=left}}; {{lit|the Self-Rulers' Army of Wales}}); and [[Fred Jones (Welsh politician)|Fred Jones]], [[Saunders Lewis]] of {{langnf|cy|Y Mudiad Cymreig|the Welsh Movement}} and D. Edmund Williams.<ref name="Ailgeni">{{cite book |title=Rebirth of a nation: Wales, 1880–1980 |last=Morgan |first=Kenneth O. |author-link=Kenneth O. Morgan |year=1981 |edition=reprint 2002 |volume=6 |series=History of Wales |publisher=Oxford University Press |location=Oxford |isbn=0-19-821760-9 |page=206 |url=https://books.google.com/books?id=asSr71jWDIEC&pg=PA254 |access-date=9 February 2011 |archive-url=https://web.archive.org/web/20160603152958/https://books.google.com/books?id=asSr71jWDIEC&pg=PA254 |archive-date=3 June 2016 |url-status=live }}</ref> Initially, home rule for Wales was not an explicit aim of the new movement; keeping Wales [[Welsh-speaking]] took primacy, with the aim of making Welsh the only official language of Wales.<ref name="Philip 1975">{{cite book |first=Alan Butt |last=Philip |title=The Welsh Question: Nationalism in Welsh Politics, 1945–1970 |url=https://archive.org/details/welshquestionnat0000phil |url-access=registration |location=Cardiff |publisher=University of Wales Press |year=1975 |isbn=0-7083-0537-7 }}</ref>

In the [[1929 United Kingdom general election|1929 general election]], the party contested its first parliamentary constituency, [[Caernarvonshire (UK Parliament constituency)|Caernarvonshire]], polling 609 votes, or 1.6% of the vote for that seat. The party contested few such elections in its early years, partly due to its ambivalence towards Westminster politics. Indeed, the candidate [[Lewis Valentine]], the party's first president, offered himself in Caernarvonshire on a platform of demonstrating Welsh people's rejection of English dominion.<ref name="McAllister 2001">{{cite book |last=McAllister |first=Laura |title=Plaid Cymru: the Emergence of a Political Party |year=2001 |location=Bridgend |publisher=Seren |isbn=1-85411-310-0 |author-link=Laura McAllister}}</ref>

===1930s===
By 1932, the aims of [[self-government]] and Welsh representation at the [[League of Nations]] had been added to that of preserving Welsh language and culture. However, this move, and the party's early attempts to develop an economic critique, did not broaden its appeal beyond that of an intellectual and [[socially conservative]] Welsh language pressure group.<ref>McAllister, L., ''Plaid Cymru: the Emergence of a Political Party'' (Seren, 2001), "The tentative moves towards elaborating and broadening Plaid's policy portfolio did not allow it to shake off its early identity as a language movement or a cultural pressure group." See also Philip, A. B., ''The Welsh Question'' (University of Wales Press, 1975), "It is clear that the Welsh Nationalist Party was at the outset essentially intellectual and moral in outlook and socially conservative."</ref> The alleged sympathy of the party's leading members (including President [[Saunders Lewis]]) towards Europe's [[totalitarianism|totalitarian regimes]] compromised its early appeal further.<ref>Morgan, K. O., ''Welsh Devolution: the Past and the Future'' in ''Scotland and Wales: Nations Again?'' (ed. Taylor, B., and Thomson, K.), (1999), University of Wales Press. Williams, G. A. ''When Was Wales?'', (1985), Penguin. Davies, J., ''A History of Wales'', (1990, rev. 2007), Penguin. Davies, D. H., ''The Welsh Nationalist Party 1925–1945'' (1983), St. Martin's Press. Morgan, K. O., ''Rebirth of a Nation'', (1981), OUP.</ref>

Saunders Lewis, David John Williams and Lewis Valentine set fire to the newly constructed RAF [[Penyberth]] air base on the [[Llŷn Peninsula]] in [[Gwynedd]] in 1936, in protest at its siting in the Welsh-speaking heartland. The leaders' treatment, including the trial judge's dismissal of the use of Welsh and their subsequent imprisonment in [[Wormwood Scrubs (HM Prison)|Wormwood Scrubs]], led to "The Three" becoming a ''[[cause célèbre]]''. This heightened the profile of the party dramatically and its membership had doubled to nearly 2,000 by 1939.<ref name="Philip 1975" /><ref name="Y tri">{{cite book |title=A companion to early twentieth-century Britain |last=Jones |first=R. Merfyn |editor1-last=Wrigley |editor1-first=Chris |year=2003 |series=Blackwell's Companion to British History |publisher=[[Wiley-Blackwell]] |location=Oxford |isbn=0-631-21790-8 |page=99 |url=https://books.google.com/books?id=GCFb2UkPYaQC&pg=PA99 |access-date=9 February 2011 |archive-url=https://web.archive.org/web/20160505071226/https://books.google.com/books?id=GCFb2UkPYaQC&pg=PA99 |archive-date=5 May 2016 |url-status=live }}</ref>

===1940s===
[[File:Plaid Cymru rally in Machynlleth in 1949 where the 'Parliament for Wales in 5 years' campaign was started (1455089).jpg|right|thumb|A Plaid Cymru rally in Machynlleth in 1949]]
Penyberth, and Plaid Cymru's neutral stance during the [[Second World War]], prompted concerns within the UK Government that it might be used by Germany to insert spies or carry out other covert operations.<ref>{{cite web |url=http://www.south-wales.police.uk/fe/master.asp?n1=8&n2=253&n3=504&n4=846 |title=Inspector Williams the Spy Catcher] |website=[[South Wales Police]] |archive-url=https://web.archive.org/web/20091112091335/http://www.south-wales.police.uk/fe/master.asp?n1=8&n2=253&n3=504&n4=846 |access-date=29 September 2006 |archive-date=12 November 2009 }}</ref> In fact, the party adopted a neutral standpoint and urged (with only limited success) [[conscientious objection]] to war service.<ref>Davies, J., ''A History of Wales'' (1990, rev. 2007), Penguin: "Saunders Lewis ... hoped that a substantial number of Welshmen would refuse to be conscripted on the grounds that they were Welsh. He was disappointed by their response."</ref>

In 1943, Saunders Lewis contested the University of Wales parliamentary seat at a by-election, gaining 1,330 votes, or 22%. In the [[1945 United Kingdom general election|1945 general election]], with party membership at around 2,500, Plaid Cymru contested seven seats, as many as it had in the preceding 20 years, including constituencies in south Wales for the first time. At this time [[Gwynfor Evans]] was elected president.<ref>{{Cite web |url=https://biography.wales/article/s10-EVAN-RIC-1912 |title=EVANS, GWYNFOR RICHARD (1912-2005), Welsh nationalist and politician |date=2016-02-24 |access-date=2023-09-09 |website=The Dictionary of Welsh Biography |last=Dafis |first=Cynog}}</ref>

===1950s===
[[File:1959 Election in Merioneth.jpg|thumb|1959 election in Merioneth. Gwynfor Evans, standing, is talking at [[Bryncrug]]]]
[[File:BBC debate between Iorwerth Thomas (Rhondda MP) and Gwynfor Evans (15171981727).jpg|alt=Iorwerth Thomas and Gwynfor Evans sitting at a table in front of a BBC microphone, debating.|thumb|BBC debate between [[Iorwerth Thomas]] (Rhondda MP - [[Labour Party (UK)|Labour]]) and [[Gwynfor Evans]], Plaid Cymru's first MP]]
Gwynfor Evans's presidency coincided with the maturation of Plaid Cymru (as it now began to refer to itself) into a more recognisable political party. Its share of the vote increased from 0.7% in the [[1951 United Kingdom general election|1951 general election]] to 3.1% in [[1955 United Kingdom general election|1955]] and 5.2% in [[1959 United Kingdom general election|1959]]. In the 1959 election, the party contested a majority of Welsh seats for the first time. Proposals to flood the village of [[Capel Celyn]] in the [[Tryweryn]] valley in Gwynedd in 1957 to supply the city of [[Liverpool]] with water played a part in Plaid Cymru's growth. The fact that the parliamentary bill authorising the dam went through without support from any Welsh MPs showed that the MPs' votes in Westminster were not enough to prevent such bills from passing.<ref>Davies, J., ''A History of Wales'' (1990, rev. 2007), Penguin.</ref>

===1960s===
Support for the party declined slightly in the early 1960s, particularly as support for the Liberal Party began to stabilise from its long-term decline. In 1962, Saunders Lewis gave a radio talk entitled ''[[Tynged yr Iaith]]'' (The fate of the language) in which he predicted the extinction of the Welsh language unless action was taken. This led to the formation of [[Cymdeithas yr Iaith Gymraeg]] (the Welsh Language Society) the same year.<ref>Morgan, K. O., ''Rebirth of a Nation'', (1981), OUP.</ref>

Labour's return to power in 1964 and the creation of the post of [[Secretary of State for Wales]] appeared to represent a continuation of the incremental evolution of a distinctive Welsh polity, following the [[Conservative Party (UK)|Conservative]] government's appointment of a Minister of Welsh Affairs in the mid-1950s and the establishment of [[Cardiff]] as Wales' capital in 1955.{{Citation needed|date=May 2023}}

However, [[1966 Carmarthen by-election|in 1966]], less than four months after coming in third in the constituency of [[Carmarthen (UK Parliament constituency)|Carmarthen]], Gwynfor Evans captured the seat from Labour at a by-election. This was followed by two further by-elections in [[Rhondda West (UK Parliament constituency)|Rhondda West]] in [[1967 Rhondda West by-election|1967]] and [[Caerphilly (UK Parliament constituency)|Caerphilly]] in [[1968 Caerphilly by-election|1968]] in which the party achieved massive swings of 30% and 40% respectively, coming within a whisker of victory. The results were caused partly by an anti-Labour backlash. Expectations in coal mining communities that the [[Harold Wilson|Wilson]] government would halt the long-term decline in their industry had been dashed by a significant downward revision of coal production estimates.<ref>Francis, H. and Smith, D., ''The Fed: A History of the South Wales Miners in the Twentieth Century'', (1980), University of Wales.</ref> However, particularly in Carmarthen, Plaid also successfully depicted Labour's policies as a threat to the viability of small Welsh communities.<ref>Tanner, D., ''Facing the New Challenge: Labour and Politics 1970–2000'' in ''The Labour Party in Wales 1900–2000'' (Ed. Tanner, D., Williams, C. and Hopkin, D.), (2000), University of Wales Press.</ref>

===1970s===
In the [[1970 United Kingdom general election|1970 general election]], Plaid Cymru contested every seat in Wales for the first time and its vote share surged from 4.5% in 1966 to 11.5%. Gwynfor Evans lost Carmarthen to Labour, but regained the seat in [[October 1974 United Kingdom general election|October 1974]], by which time the party had gained a further two MPs, representing the constituencies of [[Caernarfon (UK Parliament constituency)|Caernarfon]] and [[Merioneth (UK Parliament constituency)|Merionethshire]].<ref>{{Cite web |date=2015-05-08 |title=UK General Election results: October 1974 [Archive] |url=https://web.archive.org/web/20150508153624/http://www.politicsresources.net/area/uk/ge74b/i04.htm |access-date=2025-05-16 |website=web.archive.org}}</ref><ref>{{Cite web |date=2015-05-08 |title=UK General Election results: October 1974 [Archive] |url=https://web.archive.org/web/20150508153653/http://www.politicsresources.net/area/uk/ge74b/i14.htm |access-date=2025-05-16 |website=web.archive.org}}</ref>

Plaid Cymru's emergence (along with the [[Scottish National Party]]) prompted the Wilson government to establish the [[Kilbrandon Commission]] on the constitution. The subsequent proposals for a Welsh Assembly were, however, heavily defeated in a [[1979 Welsh devolution referendum|referendum in 1979]]. Despite Plaid Cymru's ambivalence toward home rule (as opposed to outright independence) the [[referendum]] result led many in the party to question its direction.<ref name="McAllister 2001"/>

Plaid campaigned to leave the Common Market in the [[1975 United Kingdom European Communities membership referendum|1975 referendum]],<ref>{{cite web |url=https://digital.library.lse.ac.uk/Documents/Detail/in-memory-of-wales-to-be-killed-by-the-common-market/124971 |title=In memory of Wales to be killed by the common market |website=LSE Digital Library |publisher=[[London School of Economics]] |access-date=20 March 2025 }}</ref><ref name="auto">{{cite web |url=https://www.bbc.co.uk/news/uk-politics-33045935 |title=EU referendum: Parallels with 1975 |date=10 June 2015 |access-date=17 September 2019 |work=[[BBC News]] |archive-url=https://web.archive.org/web/20190416021343/https://www.bbc.co.uk/news/uk-politics-33045935 |archive-date=16 April 2019 |url-status=live}}</ref> feeling that the EC's regional aid policies would "reconcile places like Wales to their subordinate position".<ref name="williams-brexit2">{{cite web |last1=Williams |first1=Joe |date=22 October 2019 |title=The Welsh independence movement's Brexit stance risk alienating Leave voters |url=https://nation.cymru/opinion/welsh-independence-leave-remain-eu-europe/ |access-date=23 April 2022 |publisher=[[Nation.Cymru]] |archive-date=25 July 2021 |archive-url=https://web.archive.org/web/20210725214605/https://nation.cymru/opinion/welsh-independence-leave-remain-eu-europe/ |url-status=live }}</ref> Nevertheless, 65% of Welsh voters voted to remain in the EC during a [[1975 United Kingdom European Communities membership referendum|1975 referendum]].<ref>{{cite web |date=16 June 2016 |title=Europe Referendum 1975: How BBC reported Wales results |url=https://www.bbc.co.uk/news/av/uk-36474059 |access-date=23 April 2022 |website=[[BBC News]] |archive-date=23 April 2022 |archive-url=https://web.archive.org/web/20220423204934/https://www.bbc.co.uk/news/av/uk-36474059 |url-status=live }}</ref> The EC was incorporated into the [[European Union]] (EU) in 1993.<ref>{{cite web |date=7 February 1992 |title=Treaty of Maastricht on European Union |url=http://europa.eu/legislation_summaries/economic_and_monetary_affairs/institutional_and_economic_framework/treaties_maastricht_en.htm |access-date=23 April 2022 |work=Europa web portal |publisher=Activities of the European Union |archive-date=11 October 2011 |archive-url=https://web.archive.org/web/20111011055405/http://europa.eu/legislation_summaries/economic_and_monetary_affairs/institutional_and_economic_framework/treaties_maastricht_en.htm |url-status=live }}</ref>

At the [[1979 United Kingdom general election|1979 general election]], the party's vote share declined from 10.8% to 8.1% and Carmarthen was again lost to Labour, although [[Caernarfon]] and [[Merionethshire]] were held by the party.{{Citation needed|date=May 2023}}

===1980s===
Caernarfon MP [[Dafydd Wigley]] succeeded Gwynfor Evans as president in 1981, inheriting a party whose morale was at an all-time low. In 1981 the party adopted a policy of "community socialism".<ref>{{citation|mode=cs1|title=Political Parties in Britain|first1=Matt|last1=Cole|first2=Helen|last2=Deighan|publisher=Edinburgh University Press|date=2012|page=165}}</ref> While the party embarked on a wide-ranging review of its priorities and goals, Gwynfor Evans fought a successful campaign (including the threat of a hunger strike) to oblige the Conservative government to fulfill its promise to establish [[S4C]], a Welsh-language television station.<ref>{{cite news |title=Plaid pioneer Gwynfor Evans dies |work=[[BBC News]] |date=21 April 2005 |url=http://news.bbc.co.uk/1/hi/wales/2002565.stm |access-date=31 July 2008 |quote=Mr Evans changed the face of British politics when he became Plaid's first MP in the 1966 Carmarthen by-election. Fourteen years later he threatened to starve himself to death in the cause of Welsh language television, leading to the foundation of S4C. |archive-url=https://web.archive.org/web/20090115142431/http://news.bbc.co.uk/1/hi/wales/2002565.stm |archive-date=15 January 2009 |url-status=live}}</ref> In 1984, [[Dafydd Elis-Thomas]] was elected president, defeating [[Dafydd Iwan]], a move that saw the party shift to the left. [[Ieuan Wyn Jones]] (later Plaid Cymru leader) captured [[Ynys Mon (UK Parliament constituency)|Ynys Môn]] from the Conservatives in [[1987 United Kingdom general election|1987]]. In 1989 Dafydd Wigley once again assumed the presidency of the party.{{Citation needed|date=May 2023}}

===1990s===
In the [[1992 United Kingdom general election|1992 general election]], the party added a fourth MP, [[Cynog Dafis]], when he gained [[Ceredigion and Pembroke North]] from the [[Liberal Democrats (UK)|Liberal Democrats]]. Dafis was endorsed by the local branch of the [[Wales Green Party|Green Party]]. The party's vote share recovered to 9.9% at the [[1997 United Kingdom general election|1997 general election]].{{Citation needed|date=May 2023}}

In 1997, following the election of a Labour government committed to devolution for Wales, a [[1997 Welsh devolution referendum|further referendum]] was narrowly won, establishing the [[National Assembly for Wales]]. Plaid Cymru became the main opposition to the ruling Labour Party, with 17 seats to Labour's 28. In doing so, it appeared to have broken out of its rural Welsh-speaking heartland, and gained seats in traditionally strong Labour areas in industrial [[South Wales]].<ref>{{Cite journal |last=Jones |first=R. W. |date=2006-01-01 |title=Devolution and Electoral Politics in Scotland and Wales |url=https://academic.oup.com/publius/article-lookup/doi/10.1093/publius/pji034 |journal=Publius: The Journal of Federalism |language=en |volume=36 |issue=1 |pages=115–134 |doi=10.1093/publius/pji034 |issn=0048-5950}}</ref>

Ahead of the [[1999 National Assembly for Wales election]], Plaid Cymru dropped its policy of Welsh independence in favour of continued membership in the European Union. These changes in policy were made as it was believed that the electorate in Wales did not view independence as an important issue. It also adopted [[social democracy]] for its economic policy in an attempt to weaken Labour. These changes in policy have been used to explain the party's subsequent electoral success in Labour's traditional [[South East Wales]] heartlands.<ref name=":1">{{Cite web |year=2018 |title=Welsh Nationalism: An Approach |url=https://addi.ehu.es/bitstream/handle/10810/30202/TFG_Cillero.pdf |access-date=28 December 2023 |website=Universidad del Pais Vasco |page=14}}</ref>

===Assembly/Senedd era===
[[File:Plaid Cymru Group office.jpg|thumb|Plaid Cymru Group office in the [[Senedd building]]]]

====First National Assembly (1999–2003)====
In the [[1999 National Assembly for Wales election|1999 election]], Plaid Cymru gained seats in traditional Labour areas such as [[Rhondda (National Assembly for Wales constituency)|Rhondda]], [[Islwyn (National Assembly for Wales constituency)|Islwyn]] and [[Llanelli (National Assembly for Wales constituency)|Llanelli]], achieving by far its highest share of the vote in any Wales-wide election. While Plaid Cymru regarded itself as the natural beneficiary of devolution, others attributed its performance in large part to the travails of the Labour Party{{who|date=November 2011}}, whose nomination for [[Assembly First Secretary]], [[Ron Davies (British politician)|Ron Davies]], was forced to stand down in an alleged [[sex scandal]]. The ensuing leadership battle, won by [[Alun Michael]], did much to damage Labour, and thus aided Plaid Cymru, whose leader was the more popular and higher profile [[Dafydd Wigley]]. The Labour Party's UK national leadership was seen to interfere in the contest and deny the popular [[Rhodri Morgan]] victory.<ref>{{cite news |title=Morgan is more popular — Michael |work=[[BBC News]] |date=17 February 1999 |url=http://news.bbc.co.uk/1/hi/uk_politics/281166.stm |access-date=31 July 2008 |quote=Mr Michael, who has Prime Minister Tony Blair's backing, has been widely predicted to come first due to the form of electoral system used. An electoral college composed of three groups — politicians, trade unions and party members — will determined the winner. Large unions such as AEEU that have made their choice after a ballot of a small number of delegates are backing Mr Michael, but Mr Morgan has won every union member vote, including the shopworkers' union Usdaw on Tuesday night. Mr Morgan, a left-wing backbencher, has also repeatedly topped opinion polls taken among Labour Party members in Wales. |archive-url=https://web.archive.org/web/20021231172945/http://news.bbc.co.uk/1/hi/uk_politics/281166.stm |archive-date=31 December 2002 |url-status=live }}</ref> Less than two months later, in [[1999 European Parliament election in the United Kingdom|elections to the European parliament]], Labour support slumped further, and Plaid Cymru came within 2.5% of achieving the largest share of the vote in Wales. Under the new system of [[proportional representation]], the party also gained two MEPs.{{Citation needed|date=May 2023}}

Plaid Cymru then developed political problems of its own. Dafydd Wigley resigned, citing health problems but amid rumours of a plot against him.<ref>{{cite news |title='Wigley downfall' plot denied |work=[[BBC News]] |date=14 July 2000 |url=http://news.bbc.co.uk/2/hi/uk_news/wales/832595.stm |access-date=31 July 2008 |quote=Mr Wigley's announcement that he was to give up the presidency of Plaid Cymru in May came as a shock. Although he had been in hospital undergoing heart surgery, he was expected to resume his career. Some Assembly members said privately that he had taken on too much — being an MP, AM, party president and also group leader in the National Assembly. But there was also the suggestion that there was a conspiracy to oust him. |archive-url=https://web.archive.org/web/20140202103553/http://news.bbc.co.uk/2/hi/uk_news/wales/832595.stm |archive-date=2 February 2014 |url-status=live }}</ref> His successor, [[Ieuan Wyn Jones]], struggled to impose his authority, particularly over controversial remarks made by a councillor, Seimon Glyn.<ref>{{cite news |title=Moderate with a hard act to follow |work=[[BBC News]] |date=4 April 2003 |url=http://news.bbc.co.uk/1/hi/wales/2905677.stm |access-date=31 July 2008 |quote=But Mr Jones was soon facing questions about his credentials for the job. Seimon Glyn, until then a fairly obscure Plaid Cymru councillor from Gwynedd, had made controversial comments on BBC Radio Wales about inward migration into Welsh-speaking communities. The issue was raised when Mr Jones appeared on the BBC's Question Time in Caernarfon, and he was criticised for his response, in which he at first denied that Mr Glyn had referred to English as a foreign language. There were more problems when Plaid's then chief executive said that Mr Jones was on a learning curve in the job. |archive-url=https://web.archive.org/web/20060622132648/http://news.bbc.co.uk/1/hi/wales/2905677.stm |archive-date=22 June 2006 |url-status=live }}</ref> At the same time, Labour leader and First Minister Alun Michael was replaced by Rhodri Morgan.{{Citation needed|date=May 2023}}

In the [[2001 United Kingdom general election|2001 general election]], notwithstanding Plaid Cymru recording its highest-ever vote share in a general election, 14.3%, the party lost Wyn Jones's former seat of [[Ynys Môn (UK Parliament constituency)|Ynys Môn]] to [[Albert Owen]], although it gained [[Carmarthen East and Dinefwr (UK Parliament constituency)|Carmarthen East and Dinefwr]], where [[Adam Price]] was elected.{{Citation needed|date=May 2023}}

====Second National Assembly (2003–07)====
The [[2003 National Assembly for Wales election|Assembly elections of May 2003]] saw the party's representation drop from 17 to 12, with the seats gained in the 1999 election falling again to Labour and the party's share of the vote declining to 21%. Plaid Cymru narrowly remained the second-largest party in the National Assembly ahead of the Conservatives, Liberal Democrats and [[Forward Wales]].{{Citation needed|date=May 2023}}

On 15 September 2003, [[folk music|folk-singer]] and county councillor [[Dafydd Iwan]] was elected as Plaid Cymru's president. Ieuan Wyn Jones, who had resigned from his dual role as president and Assembly group leader following the losses in the 2003 Assembly election, was re-elected in the latter role. [[Elfyn Llwyd]] remained the Plaid Cymru leader in the Westminster Parliament. Under Iwan's presidency the party formally adopted a policy of independence for Wales within Europe.{{Citation needed|date=May 2023}} Plaid Cymru had historically supported Welsh independence but dropped this policy ahead of the 1999 devolved election.<ref name=":1" />

The 2004 local election saw the party lose control of the two South Wales councils it gained in 1999, [[Rhondda Cynon Taff]] and [[Caerphilly]], while retaining its stronghold of Gwynedd in the north-west. The results enabled the party to claim a greater number of ethnic minority councillors than all the other political parties in Wales combined,<ref>{{cite web |url=http://www.epolitix.com/EN/Interviews/200609/f6812672-57e0-4c07-941d-195cbb65b1f4.htm |title=Elfyn Llwyd — Plaid Cymru parliamentary leader ePolitix interview |publisher=Epolitix.com |date=6 September 2006 |access-date=20 April 2010 |archive-url=https://web.archive.org/web/20080216165431/http://www.epolitix.com/EN/Interviews/200609/f6812672-57e0-4c07-941d-195cbb65b1f4.htm |archive-date=16 February 2008 |url-status=usurped }}</ref> along with gains in authorities such as Cardiff and [[Swansea]], where Plaid Cymru representation had been minimal. In the European Parliament elections of the same year, the party's vote share fell to 17.4%, and the reduction in the number of Welsh MEPs saw its representation reduced to one.{{Citation needed|date=May 2023}}

[[File:History of Plaid Cymru logo.jpg|thumb|Old logo (above) and new logo (below)]]

In the [[2005 United Kingdom general election|general election]] of 5 May 2005, Plaid Cymru lost the [[Ceredigion (UK Parliament constituency)|Ceredigion]] seat to the [[Liberal Democrats (UK)|Liberal Democrats]]; this result was a disappointment to Plaid, who had hoped to gain [[Ynys Môn (UK Parliament constituency)|Ynys Môn]]. Overall therefore, Plaid Cymru's Parliamentary representation fell to three seats, the lowest number for the party since 1992. The party's share of the vote fell to 12.6%.<ref>{{cite news |url=http://news.bbc.co.uk/1/shared/vote2005/html/region_10.stm |title=Election 2005 results, Wales |work=[[BBC News]] |date=1 June 2005 |access-date=20 April 2010 |archive-url=https://web.archive.org/web/20090218051930/http://news.bbc.co.uk/1/shared/vote2005/html/region_10.stm |archive-date=18 February 2009 |url-status=live }}</ref>

Since Plaid Genedlaethol Cymru reformation to 'Plaid Cymru' in 1933, the logo representing the party was the green 'triban' (three peaks) which symbolically represented Plaid's three key goals; self-government, cultural prosperity and economic prosperity, 'anchored in the bedrock of Welsh identity and history that is the Welsh upland landscape',<ref>{{cite book |isbn=978-1-4725-3373-9 |first=Marianna |last=Dudley|title=An Environmental History of the UK Defence Estate, 1945 to the Present |date=16 January 2014 |publisher=Bloomsbury Academic }}{{Page needed|date=August 2022}}</ref> the logo would change in the late stages of 20th century to include the red dragon of Wales, however this version was short-lived. In 2006, the party voted constitutional changes to formally designate the party's leader in the assembly as its overall leader, with [[Ieuan Wyn Jones]] being restored to the full leadership and [[Dafydd Iwan]] becoming head of the voluntary wing of the party.<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/wales/4718082.stm |title=UK &#124; Wales &#124; Jones 'to return as Plaid leader' |work=[[BBC News]] |date=2006-02-16 |access-date=2022-08-06 |archive-date=29 June 2006 |archive-url=https://web.archive.org/web/20060629154901/http://news.bbc.co.uk/1/hi/wales/4718082.stm |url-status=live }}</ref> The party unveiled a radical change of image in 2006. In that year, the party opted to use "Plaid" as the party's name, although "Plaid Cymru — the Party of Wales" would remain the official title. Plaid would abandon the triban (apart from the merchandise) and adopt the yellow [[Welsh poppy]] (''Meconopsis cambrica'').<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/wales/south_west/4744956.stm |title=Plaid image change 'a new start' |work=[[BBC News]] |date=24 February 2006 |access-date=6 May 2016 |archive-date=6 August 2022 |archive-url=https://web.archive.org/web/20220806084526/http://news.bbc.co.uk/2/hi/uk_news/wales/south_west/4744956.stm |url-status=live }}</ref>

====Third National Assembly (2007–2011)====
In the [[2007 National Assembly for Wales election|National Assembly election]] of 3 May 2007, Plaid Cymru increased its number of seats from 12 to 15, regaining [[Llanelli (National Assembly for Wales constituency)|Llanelli]], gaining one additional list seat and winning the newly created constituency of [[Aberconwy (National Assembly for Wales constituency)|Aberconwy]]. The 2007 election also saw Plaid Cymru's [[Mohammad Asghar]] become the first ethnic minority candidate elected to the Welsh Assembly.<ref>{{cite news |title=First ethnic minority AM elected |work=[[BBC News]] |date=4 May 2007 |url=http://news.bbc.co.uk/1/hi/wales/6622925.stm |access-date=6 May 2007 |quote=The assembly has its first ethnic minority member with the election of Plaid Cymru's Mohammad Asghar on the regional list. Mr Asghar, who was second on the Plaid list, was the fourth and final AM to be elected in South Wales East. |archive-url=https://web.archive.org/web/20070516223542/http://news.bbc.co.uk/1/hi/wales/6622925.stm |archive-date=16 May 2007 |url-status=live }}</ref> The party's share of the vote increased to 22.4%.<ref>{{Cite web |date=2023-12-04 |title=BBC NEWS {{!}} Election 2007 {{!}} Welsh Assembly {{!}} Election Result: Wales |url=http://news.bbc.co.uk/1/shared/vote2007/welshasssembly_english/html/scoreboard_99999.stm |archive-url=https://web.archive.org/web/20231204230424/http://news.bbc.co.uk/1/shared/vote2007/welshasssembly_english/html/scoreboard_99999.stm |url-status=dead |archive-date=2023-12-04 |access-date=2025-03-23 }}</ref>

After weeks of negotiations involving all four parties in the Assembly, Plaid Cymru and Labour agreed to form a [[coalition government]]. Their agreed "[[One Wales]]" programme included a commitment for both parties to campaign for a Yes vote in a [[2011 Welsh devolution referendum|referendum on full law-making powers]] for the Assembly, to be held at a time of the Welsh Assembly Government's choosing.<ref name=":2">{{cite news |title=Details of Labour–Plaid agreement |work=[[BBC News]] |date=27 June 2007 |url=http://news.bbc.co.uk/1/hi/wales/6246428.stm |access-date=31 July 2008 |quote=On the sensitive issue of giving the Welsh assembly full law-making powers, a referendum on the issue is promised "as soon as practicable, at or before the end of the assembly term (in 2011)". According to the document "both parties will then take account of the success of the bedding down of the use of the new legislative powers (which came in after last May's election) already available and, by monitoring the state of public opinion, will need to assess the levels of support for full law-making powers necessary to trigger the referendum". |archive-date=6 August 2022 |archive-url=https://web.archive.org/web/20220806084527/http://news.bbc.co.uk/2/hi/uk_news/wales/6246428.stm |url-status=live }}</ref> Ieuan Wyn Jones was subsequently confirmed as [[First Minister of Wales|Deputy First Minister of Wales]]<ref>{{cite news |title=Jones confirmed as deputy leader |work=[[BBC News]] |date=11 July 2007 |url=http://news.bbc.co.uk/1/hi/wales/6290480.stm |access-date=31 July 2008 |quote=Plaid Cymru leader Ieuan Wyn Jones said it was a "great honour" to become the Welsh assembly's Deputy First Minister. He was Plaid's first government minister in the party's 82-year history. In accepting the post as part of the coalition deal with Labour, Mr Jones said it was an "historic statement" personally and for his party. |archive-url=https://web.archive.org/web/20071009061517/http://news.bbc.co.uk/1/hi/wales/6290480.stm |archive-date=9 October 2007 |url-status=live }}</ref> and [[Minister for the Economy and Transport]]. [[Rhodri Glyn Thomas]] was appointed Heritage Minister. He later stood down, and [[Alun Ffred Jones]] took over. Ceredigion AM [[Elin Jones]] was appointed to the Rural Affairs brief in the new 10-member cabinet. [[Jocelyn Davies]] became Deputy Minister for Housing, and later, Regeneration.{{Citation needed|date=May 2023}}

In the [[2010 United Kingdom general election|2010 general election]], Plaid returned three MPs to Westminster. They took part in the [[Yes for Wales]] cross-party campaign for the March 2011 referendum.{{Citation needed|date=May 2023}}

====Fourth National Assembly (2011–16)====
In the [[2011 National Assembly for Wales election|2011 National Assembly election]], Plaid slipped from second place to third, being overtaken by the [[Welsh Conservatives]] and losing its deputy leader [[Helen Mary Jones]]. The party held an inquiry into the election result.<ref>{{cite news |title=Plaid plans review of election catastrophe |date=10 May 2011 |work=Wales Online |url=http://www.walesonline.co.uk/news/welsh-politics/welsh-politics-news/2011/05/10/plaid-plans-review-of-election-catastrophe-91466-28663985/ |access-date=16 May 2011 |archive-url=https://web.archive.org/web/20121014105311/http://www.walesonline.co.uk/news/welsh-politics/welsh-politics-news/2011/05/10/plaid-plans-review-of-election-catastrophe-91466-28663985/ |archive-date=14 October 2012 |url-status=live }}</ref> The internal investigation led to the adoption of wide-ranging changes to its constitution, including a streamlining of the leadership structure.<ref>{{cite news |title=Plaid Cymru agrees new constitution at special Aberystwyth conference |work=[[BBC News]] |date=16 February 2013 |url=https://www.bbc.co.uk/news/uk-wales-politics-21479687 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20161213073019/http://www.bbc.co.uk/news/uk-wales-politics-21479687 |archive-date=13 December 2016 |url-status=live }}</ref>

In May 2011, Ieuan Wyn Jones announced he would stand down as leader within the first half of the Assembly term.<ref>{{cite news |url=https://www.bbc.co.uk/news/uk-wales-13389407 |work=[[BBC News]] |location=UK |title=Ieuan Wyn Jones to stand down as Plaid Cymru leader |date=13 May 2011 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20170530040119/http://www.bbc.co.uk/news/uk-wales-13389407 |archive-date=30 May 2017 |url-status=live }}</ref> A leadership election was held in which three candidates eventually stood: [[Elin Jones]], [[Dafydd Elis-Thomas]] and [[Leanne Wood]];<ref>{{cite news |title=Plaid Cymru leadership: Profiles of the three candidates |work=[[BBC News]] |date=27 January 2012 |url=https://www.bbc.co.uk/news/uk-wales-politics-16746098 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20170530121132/http://www.bbc.co.uk/news/uk-wales-politics-16746098 |archive-date=30 May 2017 |url-status=live }}</ref> [[Simon Thomas (politician)|Simon Thomas]] withdrew his candidacy before ballots were cast.<ref>{{cite news |url=http://www.golwg360.com/newyddion/cymru/64626-simon-thomas-yn-tynnu-n-ol-o-ras-arweinyddiaeth-plaid |work=Golwg360 |title=Simon Thomas yn tynnu'n ôl o ras arweinyddiaeth Plaid |date=15 March 2012 |access-date=4 September 2013 |archive-url=https://web.archive.org/web/20130926005105/http://www.golwg360.com/newyddion/cymru/64626-simon-thomas-yn-tynnu-n-ol-o-ras-arweinyddiaeth-plaid |archive-date=26 September 2013 |url-status=live }}</ref>

On 15 March 2012, Plaid Cymru elected Leanne Wood as its new leader. She received 55% of the vote, over second-placed Elin Jones with 41%.<ref>{{cite news |url=https://www.bbc.co.uk/newyddion/17381134d |work=[[Newyddion]] |publisher=[[BBC Cymru]] |title=Leanne Wood yw arweinydd newydd Plaid Cymru |date=6 February 2012}}</ref> Wood was the party's first female leader, and its first not to be a fluent Welsh speaker.<ref name=":3">{{cite news |url=https://www.bbc.co.uk/news/uk-wales-politics-17381377 |work=[[BBC News]] |title=Plaid Cymru elect Leanne Wood as new leader |date=15 March 2012 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20181225110437/https://www.bbc.co.uk/news/uk-wales-politics-17381377 |archive-date=25 December 2018 |url-status=live }}</ref><ref>{{cite news |url=http://www.walesonline.co.uk/news/wales-news/2012/03/15/leanne-wood-becomes-first-female-leader-of-plaid-cymru-91466-30546068/ |title=Leanne Wood becomes first female leader of Plaid Cymru |work=WalesOnline |date=23 March 2012 |access-date=13 August 2012 |archive-date=6 August 2022 |archive-url=https://web.archive.org/web/20220806084527/https://www.walesonline.co.uk/news/wales-news/leanne-wood-becomes-first-female-2045084 |url-status=live }}</ref> Soon after her election as leader, she appointed former MP [[Adam Price]] to head an economic commission for the party "focussed on bringing together tailor-made policies in order to transform our economy".<ref>{{cite web |url=http://www.partyofwales.org/news/2012/03/21/new-plaid-cymru-leader-unveils-economic-commission |title=New Plaid Cymru Leader Unveils Economic Commission |publisher=Plaid Cymru |date=21 March 2012 |access-date=21 September 2013 |archive-url=https://web.archive.org/web/20130928052541/http://www.partyofwales.org/news/2012/03/21/new-plaid-cymru-leader-unveils-economic-commission |archive-date=28 September 2013 }}</ref><ref>{{cite news |url=https://www.bbc.co.uk/news/uk-wales-politics-17499893 |title=Adam Price: WDA was 'thrown away' and Wales needs new economic powerhouse |work=[[BBC News]] |date=25 March 2012 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20140107025418/http://www.bbc.co.uk/news/uk-wales-politics-17499893 |archive-date=7 January 2014 |url-status=live }}</ref> On 1 May 2012, it was confirmed Leanne Wood would not be taking the £23,000 pay increase that every other party leader in the Assembly receives.<ref>{{cite news |url=http://www.dailypost.co.uk/news/north-wales-news/plaid-leader-leanne-wood-turns-2660022 |title=Plaid leader Leanne Wood turns down pay rise |newspaper=[[Daily Post (North Wales)|Daily Post]] |date=1 May 2012 |access-date=21 September 2013 |archive-url=https://web.archive.org/web/20160317195128/http://www.dailypost.co.uk/news/north-wales-news/plaid-leader-leanne-wood-turns-2660022 |archive-date=17 March 2016 |url-status=live }}</ref>

On 12 November 2012, Wood announced she would aim to abandon her relatively safe list seat by winning a constituency at the 2016 National Assembly elections;<ref>{{cite web |url=http://www.golwg360.com/newyddion/cymru/91492-leanne-wood-i-sefyll-mewn-sedd-etholaeth-yn-2016 |title=Leanne Wood am sefyll mewn sedd etholaeth yn 2016 |publisher=Golwg 360 |date=12 November 2012 |access-date=21 September 2013 |archive-url=https://web.archive.org/web/20130925230932/http://www.golwg360.com/newyddion/cymru/91492-leanne-wood-i-sefyll-mewn-sedd-etholaeth-yn-2016 |archive-date=25 September 2013 |url-status=live }}</ref> she later confirmed she would contest the [[Rhondda (Assembly constituency)|Rhondda]].<ref>{{cite web |url=https://www.bbc.co.uk/newyddion/21805446 |title=Leanne Wood i ymladd etholaeth Rhondda yn 2016 |publisher=[[BBC Cymru]] |date=15 March 2013 |access-date=25 December 2019 |archive-url=https://web.archive.org/web/20140420061241/http://www.bbc.co.uk/newyddion/21805446 |archive-date=20 April 2014 |url-status=live }}</ref> Adam Price was subsequently selected as the party's candidate for [[Carmarthen East and Dinefwr (UK Parliament constituency)|Carmarthen East and Dinefwr]].<ref>{{cite web |url=https://www.bbc.co.uk/news/uk-wales-politics-23284160 |title=Ex-Plaid Cymru MP Adam Price to stand for Welsh assembly |publisher=[[BBC Cymru]] |date=12 July 2013 |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20140107074500/http://www.bbc.co.uk/news/uk-wales-politics-23284160 |archive-date=7 January 2014 |url-status=live }}</ref> Lindsay Whittle confirmed he would stand solely in [[Caerphilly (National Assembly for Wales constituency)|Caerphilly]].<ref>{{cite web |url=http://www.caerphillyobserver.co.uk/news/913696/lindsay-whittle-chosen-as-caerphilly-assembly-candidate |title=Lindsay Whittle chosen as Caerphilly Assembly candidate |work=Caerphilly Observer |date=16 September 2013 |access-date=21 September 2013 |archive-url=https://web.archive.org/web/20131002085037/http://www.caerphillyobserver.co.uk/news/913696/lindsay-whittle-chosen-as-caerphilly-assembly-candidate/ |archive-date=2 October 2013 |url-status=live}}</ref>

On 20 June 2013, former party leader Ieuan Wyn Jones stood down from the Assembly as the member for [[Ynys Môn (National Assembly for Wales constituency)|Ynys Môn]].<ref>{{cite news |url=https://www.bbc.co.uk/newyddion/22989983 |title=Ieuan Wyn am sefyll i lawr yn syth |publisher=[[BBC Cymru]] |access-date=25 December 2019 |archive-url=https://web.archive.org/web/20140107002258/http://www.bbc.co.uk/newyddion/22989983 |archive-date=7 January 2014 |url-status=live}}</ref> Plaid Cymru's candidate [[Rhun ap Iorwerth]] was elected as the new Assembly Member for the constituency, receiving 12,601 votes (a 58% share) with a majority of 9,166 over the Labour candidate.<ref>{{cite web |title=Canlyniadau'r etholiad ar gyfer Ynys Môn |language=Welsh |trans-title=Election results for Anglesey |url=http://www.senedd.cynulliadcymru.org/mgElectionAreaResults.aspx?ID=50 |website=[[National Assembly for Wales]] |access-date=4 September 2013 |archive-url=https://web.archive.org/web/20130926034834/http://www.senedd.cynulliadcymru.org/mgElectionAreaResults.aspx?ID=50 |archive-date=26 September 2013 |url-status=live}}</ref>

====Fifth National Assembly/Senedd (2016–2021)====
At the [[2016 National Assembly for Wales election|2016 Welsh Assembly elections]], Plaid Cymru gained one seat, [[Rhondda (Assembly constituency)|Rhondda]] from Labour, on an otherwise disappointing night,<ref>{{cite web |last1=Browne |first1=Adrian |title=Reflections on seven Welsh elections - 1999 to 2026 |url=https://www.bbc.co.uk/news/articles/cj9eevdy4r3o |website=BBC News |access-date=8 May 2025}}</ref> in what was  became the Assembly's second-largest party and briefly became the official opposition to the Welsh Government with 12 seats.<ref name=":4">{{cite news |url=https://www.theguardian.com/politics/2016/may/06/labour-wales-plaid-cymru-takes-rhondda-plaid-cymru |title=Labour holds Wales despite serious losses |last=Morris |first=Steven |date=6 May 2016 |newspaper=[[The Guardian]] |location=London |issn=0261-3077 |language=en-GB |access-date=10 February 2017 |archive-url=https://web.archive.org/web/20170211081623/https://www.theguardian.com/politics/2016/may/06/labour-wales-plaid-cymru-takes-rhondda-plaid-cymru |archive-date=11 February 2017 |url-status=live}}</ref> By January 2018 Plaid Cymru had been reduced to ten Assembly Members, following the resignation of [[Dafydd Elis-Thomas]] in 2016<ref>{{cite news |url=http://www.walesonline.co.uk/news/politics/lord-dafydd-elis-thomas-quits-12029217 |title=Lord Dafydd Elis-Thomas quits Plaid Cymru |last=Shipton |first=Martin |date=14 October 2016 |newspaper=WalesOnline |access-date=10 February 2017 |archive-url=https://web.archive.org/web/20170211080305/http://www.walesonline.co.uk/news/politics/lord-dafydd-elis-thomas-quits-12029217 |archive-date=11 February 2017 |url-status=live }}</ref><ref>{{cite news |url=http://www2.partyof.wales/acau_ams |title=Assembly Members |newspaper=The Party of Wales |access-date=10 February 2017 |language=en |archive-url=https://web.archive.org/web/20170211075603/http://www2.partyof.wales/acau_ams |archive-date=11 February 2017 |url-status=live }}</ref> and the permanent expulsion of [[Neil McEvoy]] from Plaid's Assembly group in 2018.<ref>{{cite web |url=https://www.walesonline.co.uk/news/politics/neil-mcevoy-expelled-plaid-cymru-14164997 |title=Neil McEvoy expelled from Plaid Cymru Assembly group |first=Martin |last=Shipton |date=16 January 2018 |website=Walesonline.co.uk |access-date=21 June 2018 |archive-url=https://web.archive.org/web/20180621221247/https://www.walesonline.co.uk/news/politics/neil-mcevoy-expelled-plaid-cymru-14164997 |archive-date=21 June 2018 |url-status=live }}</ref>

Despite campaigning to leave in [[1975 United Kingdom European Communities membership referendum|1975]],<ref name="auto"/> Plaid campaigned for a Remain vote in the [[2016 United Kingdom European Union membership referendum|2016 referendum on the UK's membership of the EU]],<ref>{{cite web |url=https://www.bbc.co.uk/news/uk-wales-politics-35532863 |title=Plaid: Stay in EU to solve its problems |date=10 February 2016 |access-date=21 June 2018 |work=[[BBC News]] |archive-url=https://web.archive.org/web/20180531203613/http://www.bbc.co.uk/news/uk-wales-politics-35532863 |archive-date=31 May 2018 |url-status=live }}</ref> spending £27,495 on the campaign.<ref>{{cite web |url=https://www.electoralcommission.org.uk/who-we-are-and-what-we-do/elections-and-referendums/past-elections-and-referendums/eu-referendum/campaign-spending-eu-referendum |title=Campaign spending at the EU referendum |date=29 July 2019 |website=Electoral Commission |access-date=8 September 2020 |archive-date=6 August 2020 |archive-url=https://web.archive.org/web/20200806035256/https://www.electoralcommission.org.uk/who-we-are-and-what-we-do/elections-and-referendums/past-elections-and-referendums/eu-referendum/campaign-spending-eu-referendum |url-status=live }}</ref> In the referendum Wales voted 52.5% in favour of Leave.<ref>{{cite web |url=https://www.bbc.co.uk/news/uk-politics-eu-referendum-36612308 |title=Welsh voters back Leave in EU poll |date=24 June 2016 |access-date=21 June 2018 |work=[[BBC News]] |archive-url=https://web.archive.org/web/20180527080335/http://www.bbc.co.uk/news/uk-politics-eu-referendum-36612308 |archive-date=27 May 2018 |url-status=live }}</ref> Immediately after the referendum, Leanne Wood stated that voters 'must be respected' and criticised calls for a second EU referendum.<ref>{{cite web |url=https://www.walesonline.co.uk/news/politics/leanne-wood-says-voters-must-11564187 |title=Leanne Wood says voters 'must be respected' – and criticises calls for a second EU referendum |first=Martin |last=Shipton |date=4 July 2016 |access-date=10 December 2018 |website=Wales Online |archive-url=https://web.archive.org/web/20181210154706/https://www.walesonline.co.uk/news/politics/leanne-wood-says-voters-must-11564187 |archive-date=10 December 2018 |url-status=live }}</ref> Plaid Cymru later modified their policy to support a [[People's Vote]].<ref>{{cite news |url=https://www.bbc.co.uk/news/uk-wales-politics-45787465 |title=Plaid MPs 'will join SNP in backing new Brexit referendum' |date=8 October 2018 |access-date=10 December 2018 |work=[[BBC News]] |archive-url=https://web.archive.org/web/20181210165011/https://www.bbc.co.uk/news/uk-wales-politics-45787465 |archive-date=10 December 2018 |url-status=live }}</ref>

In the [[2017 United Kingdom general election in Wales|2017 United Kingdom general election]], Plaid saw their popular vote fall, but narrowly gained Ceredigion and saw Arfon become highly marginal.<ref>{{cite news |last=Harries |first=Robert |date=2017-06-09 |title=Plaid Cymru have their youngest ever MP after a dramatic night in Ceredigion |url=http://www.walesonline.co.uk/news/politics/plaid-cymru-youngest-ever-mp-13161824 |access-date=2021-05-13 |work=WalesOnline |language=en |archive-date=22 January 2018 |archive-url=https://web.archive.org/web/20180122005516/http://www.walesonline.co.uk/news/politics/plaid-cymru-youngest-ever-mp-13161824 |url-status=live }}</ref>

In September 2018, Adam Price won the party's [[2018 Plaid Cymru leadership election|leadership election]], defeating the incumbent Leanne Wood and fellow challenger [[Rhun ap Iorwerth]].<ref>{{Cite news |date=2018-09-28 |title=Plaid Cymru leadership contest: Adam Price wins |language=en-GB |work=[[BBC News]] |url=https://www.bbc.com/news/uk-wales-politics-45656718 |access-date=2021-05-13 |archive-date=12 November 2018 |archive-url=https://web.archive.org/web/20181112091554/https://www.bbc.com/news/uk-wales-politics-45656718 |url-status=live }}</ref> In October 2018, [[Left-wing populism|left-wing populist]] by Massetti Emmanuel in the [[Comparative European Politics]] academic journal.<ref name="Springer">{{Cite journal |first=Massetti |last=Emmanuel |url=https://link.springer.com/article/10.1057/s41295-018-0136-z |title=Left-wing regionalist populism in the 'Celtic' peripheries: Plaid Cymru and the Scottish National Party's anti-austerity challenge against the British elite |journal=Comparative European Politics |date=2018 |volume=16 |issue=6 |pages=937–953 |doi=10.1057/s41295-018-0136-z |access-date=16 March 2023}}</ref>

In the [[2019 Brecon and Radnorshire by-election|Brecon and Radnorshire by-election]] Plaid Cymru decided not to put up a candidate, but instead to support the Liberal Democrat candidate [[Jane Dodds]] in order to maximise the chance of an anti-Brexit candidate winning.<ref name="Mason 2019">{{cite news |last=Mason |first=Chris |title=Remain parties team up for Brecon and Radnorshire by-election |work=[[BBC News]] |date=4 July 2019 |url=https://www.bbc.com/news/uk-politics-48871729 |access-date=17 September 2019 |archive-url=https://web.archive.org/web/20190818235817/https://www.bbc.com/news/uk-politics-48871729 |archive-date=18 August 2019 |url-status=live }}</ref>

In the [[2019 United Kingdom general election in Wales|2019 United Kingdom general election]], Plaid stood aside in four seats to endorse [[Unite to Remain]] candidates.<ref>{{cite news |url=https://www.independent.co.uk/news/uk/politics/general-election-liberal-democrats-green-plaid-cymru-unite-to-remain-alliance-swinson-a9188606.html |title=General election: Lib Dems agree 'Remain alliance' with Greens and Plaid Cymru |last=Gregory |first=Andy |date=7 November 2019 |newspaper=[[The Independent]] |location=London |access-date=24 November 2021 |archive-date=24 November 2021 |archive-url=https://web.archive.org/web/20211124180454/https://www.independent.co.uk/news/uk/politics/general-election-liberal-democrats-green-plaid-cymru-unite-to-remain-alliance-swinson-a9188606.html |url-status=live }}</ref> Plaid held their four seats but saw a decrease in their popular vote.<ref>{{cite news |url=https://www.bbc.co.uk/news/election-2019-50768482 |title=General Election 2019: Plaid hold Wales' most marginal seat |date=13 December 2019 |work=[[BBC News]] |access-date=24 November 2021 |archive-date=24 November 2021 |archive-url=https://web.archive.org/web/20211124180454/https://www.bbc.co.uk/news/election-2019-50768482 |url-status=live }}</ref>

====Sixth Senedd (2021–)====
In the run-up to the [[2021 Senedd election]], polling suggested that Welsh Labour would win the highest number of seats but fall short of an overall majority. Pollsters and commentators suggested that the most likely outcome would be another Labour–Plaid Cymru coalition,<ref>{{cite news |last=de La Mare |first=Tess |date=2 May 2021 |title=Plaid Cymru bullish as Welsh Labour hints at coalition plans post election |url=https://www.standard.co.uk/news/uk/mark-drakeford-plaid-cymru-sophy-ridge-sky-news-wales-b932869.html |access-date=13 May 2021 |newspaper=[[Evening Standard]] |place=London |language=en |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513160614/https://www.standard.co.uk/news/uk/mark-drakeford-plaid-cymru-sophy-ridge-sky-news-wales-b932869.html |url-status=live }}</ref><ref name="coalition">{{cite news |last=Morgan Jones |first=Ifan |date=23 March 2021 |title=Are we heading for a second Plaid-Labour coalition in Wales, and if so what could they agree on? |url=https://nation.cymru/opinion/are-we-heading-for-a-second-plaid-labour-coalition-in-wales-and-if-so-what-could-they-agree-on/ |access-date=13 May 2021 |work=[[Nation.Cymru]] |language=en-GB |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513160614/https://nation.cymru/opinion/are-we-heading-for-a-second-plaid-labour-coalition-in-wales-and-if-so-what-could-they-agree-on/ |url-status=live }}</ref> an option First Minister [[Mark Drakeford]] said he would be open to.<ref>{{cite news |date=2021-05-02 |title=Drakeford leaves door open to Plaid Cymru coalition |url=https://www.gwalianews.cymru/post/drakeford-leaves-door-open-to-plaid-cymru-coalition |access-date=2021-05-13 |website=Gwalia News |language=en-GB |archive-date=6 August 2022 |archive-url=https://web.archive.org/web/20220806084528/https://www.gwalianews.cymru/post/drakeford-leaves-door-open-to-plaid-cymru-coalition |url-status=live }}</ref> Price insisted that his party would not be Labour's "junior partner",<ref>{{cite news |last=Hayward |first=Will |date=2020-10-02 |title='Anything less than First Minister is a failure': Adam Price on his hopes for Plaid in the 2021 Senedd election |url=https://www.walesonline.co.uk/news/politics/adam-price-plaid-cymru-conference-19026543 |access-date=2021-05-13 |work=WalesOnline |language=en-GB |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513160614/https://www.walesonline.co.uk/news/politics/adam-price-plaid-cymru-conference-19026543 |url-status=live }}</ref> nor would they work with the Conservatives under any circumstances.<ref>{{cite news |date=2020-10-02 |title=Adam Price: 'No coalition under any circumstances with Conservatives' |url=https://nation.cymru/news/adam-price-no-coalition-under-any-circumstances-with-conservatives/ |access-date=2021-05-13 |work=[[Nation.Cymru]] |language=en-GB |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513160614/https://nation.cymru/news/adam-price-no-coalition-under-any-circumstances-with-conservatives/ |url-status=live }}</ref> He stated that Plaid would be willing to join forces with Labour, but only if the former were the largest party or if it were an equal partnership.<ref name="coalition"/> Price also said that he did not consider [[Welsh independence]] to be "a distraction or a constitutional abstraction", but rather "a practical necessity".<ref>{{cite web |last=Mosalski |first=Ruth |date=2021-04-24 |title=The Adam Price election interview: Independence isn't a distraction |url=https://www.walesonline.co.uk/news/adam-price-senedd-election-plaid-20437249 |access-date=2021-05-13 |website=WalesOnline |language=en |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513162437/https://www.walesonline.co.uk/news/adam-price-senedd-election-plaid-20437249 |url-status=live }}</ref>

At the election, Plaid increased their seat total to thirteen, up one from the twelve they won in 2016, but lost out in their target constituencies, and lost [[Rhondda (Senedd constituency)|Rhondda]] where former leader Leanne Wood lost her seat to Labour.<ref>{{cite news |last=Mosalski |first=Ruth |date=11 May 2021 |title=Plaid's goal of independence took a step back in the election - Leanne Wood |url=https://www.walesonline.co.uk/news/politics/leanne-wood-says-plaids-goal-20574143 |access-date=13 May 2021 |website=WalesOnline |language=en-GB |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513095920/https://www.walesonline.co.uk/news/politics/leanne-wood-says-plaids-goal-20574143 |url-status=live }}</ref> Price said he would not resign, telling [[ITV Wales]]: "My job is to lead, its not to give up at a set back or disappointment. My job is to sustain the hope – all those young people who voted for Plaid because they were inspired by our message of the potential we believe is there in Wales to deliver a decent society for our people. I firmly believe that we have sown a lot of seed at this election. A lot of young people in particular who did come with us this time has laid the foundations for the future which I think will set us up for growth in the years to come."<ref>{{cite news |url=https://nation.cymru/news/plaid-cymru-leader-adam-price-wont-resign-following-election-disappointment/ |title=Plaid Cymru leader Adam Price won't resign following election disappointment |date=12 May 2021 |work=[[Nation.Cymru]] |access-date=12 May 2021 |archive-date=12 May 2021 |archive-url=https://web.archive.org/web/20210512130717/https://nation.cymru/news/plaid-cymru-leader-adam-price-wont-resign-following-election-disappointment/ |url-status=live }}</ref>

On 22 November 2021, despite Price's earlier comments about refusing to work with Labour,<ref>{{cite news |last=Price |first=Adam |date=23 November 2021 |title=Adam Price explains why he did a deal with Labour |url=https://www.walesonline.co.uk/news/politics/labour-plaid-deal-adam-price-22236581 |access-date=24 November 2021 |website=WalesOnline |language=en-GB |archive-date=23 November 2021 |archive-url=https://web.archive.org/web/20211123234458/https://www.walesonline.co.uk/news/politics/labour-plaid-deal-adam-price-22236581 |url-status=live }}</ref> the two parties announced a [[2021 Welsh Labour–Plaid Cymru agreement|co-operation agreement consisting of almost 50 different policies]], including providing free school meals for all primary school children, the establishment of a free-at-point-of-need national care system and building a railway between [[North Wales|North]] and [[South Wales]].<ref>{{cite news |title=Labour and Plaid Cymru agree Welsh government co-operation deal |url=https://www.thenational.scot/news/19732552.labour-plaid-cymru-agree-welsh-government-co-operation-deal/ |last=Webster |first=Laura |date=22 November 2021 |access-date=24 November 2021 |newspaper=[[The National (Scotland)|The National]] |place=Glasgow |language=en |archive-date=6 August 2022 |archive-url=https://web.archive.org/web/20220806084527/https://www.thenational.scot/news/19732552.labour-plaid-cymru-agree-welsh-government-co-operation-deal/ |url-status=live }}</ref> Price called the agreement "a down-payment on independence" and claimed that the results of the Senedd election "confirmed Wales's status as an indy-curious nation. A curiosity that will give birth – sooner than many think – to an independent Wales." He went on to say, "For Wales to be free, we must first be united. And, that is what this Co-operation Agreement sets out to achieve. It launches us on a pathway to a united Wales, one that, sooner than we perhaps think, will find it both comfortable and natural, indeed essential, to join the world community of normal, independent nations."<ref>{{cite news |url=https://www.itv.com/news/wales/2021-11-26/does-plaid-cymrus-co-op-deal-signal-a-down-payment-on-welsh-independence |title=Adam Price: Labour and Plaid's co-op agreement is a 'down-payment on independence' |date=26 November 2021 |work=[[ITV News]] |access-date=26 November 2021 |archive-date=27 November 2021 |archive-url=https://web.archive.org/web/20211127072846/https://www.itv.com/news/wales/2021-11-26/does-plaid-cymrus-co-op-deal-signal-a-down-payment-on-welsh-independence |url-status=live }}</ref>

The co-operation agreement was ratified by Plaid's conference, with 94% voting in favour. "This is a huge step forward for Wales and our democracy," Price said. "The co-operation agreement will bring immediate, tangible and long-term benefit for the people of Wales. All primary school children will now receive free school meals; there will be free childcare for all two-year-olds; and radical action to tackle the housing crisis. There will be stability payments to support family farms; exploration of an accelerated pathway to net zero by 2035; the creation of [[Ynni Cymru]] – a company to expand community-owned renewable energy generation; and a new and reformed Senedd – bigger, more diverse, and gender balanced in law. From feeding our children to caring for our elderly, this is a nation-building Programme for Government which will change the lives of thousands of people the length and breadth of our country for the better. And none of it would be happening without Plaid Cymru."<ref>{{cite news |url=https://nation.cymru/news/plaid-cymru-conference-votes-in-favour-of-co-operation-agreement-with-welsh-government/ |title=Plaid Cymru conference votes in favour of co-operation agreement with Welsh Government |date=27 November 2021 |work=[[Nation.Cymru]] |access-date=27 November 2021 |archive-date=27 November 2021 |archive-url=https://web.archive.org/web/20211127174318/https://nation.cymru/news/plaid-cymru-conference-votes-in-favour-of-co-operation-agreement-with-welsh-government/ |url-status=live }}</ref>

In May 2023, the publication of a report which detailed failings by the party to prevent sexual harassment and bullying led to media coverage suggesting that Price had agreed to resign the party leadership,<ref name=":6">{{cite news |date=9 May 2023 |title=Adam Price to quit as Plaid Cymru leader |work=Nation.Cymru |url=https://nation.cymru/news/adam-price-to-quit-as-plaid-cymru-leader/ |access-date=9 May 2023}}</ref><ref>{{cite web |last=Deans |first=David |date=10 May 2023 |title=Adam Price: Plaid Cymru leader's future in doubt |url=https://www.bbc.co.uk/news/uk-wales-politics-65540930 |publisher=BBC News}}</ref> and Price confirmed this in a statement on 10 May. Acknowledging that he "no longer had the united support of [his] colleagues", Price stated that he would step down officially at the start of the following week, once the process for electing a new interim leader was finalised.<ref>{{cite web |last=Deans |first=David |date=11 May 2023 |title=Plaid Cymru leader Adam Price quits after damning report |url=https://www.bbc.co.uk/news/uk-wales-65553413 |publisher=BBC Wales}}</ref><ref>{{cite web |last1=Adu |first1=Aletha |last2=Badshah |first2=Nadeem |date=11 May 2023 |title=Plaid Cymru leader Adam Price steps down after damning report |url=https://www.theguardian.com/politics/2023/may/10/plaid-cymru-leader-adam-price-future-in-doubt-damning-review-detoxify |work=[[The Guardian]]}}</ref> On 11 May Plaid Cymru announced that [[Llyr Gruffydd]], Senedd member for North Wales, would replace him as interim party leader, and that this would be confirmed by the NEC on 13 May.<ref>{{cite web |date=11 May 2023 |title=Plaid Cymru: Llyr Gruffydd interim leader after Price quits |url=https://www.bbc.co.uk/news/uk-wales-politics-65556917 |publisher=BBC Wales}}</ref> On 16 June 2023 [[Rhun ap Iorwerth]] was announced as the new permanent leader after he was elected unopposed.<ref name=":7">{{Cite news |date=2023-06-16 |title=Plaid Cymru: Rhun ap Iorwerth takes over as party leader |language=en-GB |work=BBC News |url=https://www.bbc.com/news/uk-wales-politics-65928575 |access-date=2023-06-16}}</ref>

At party conference in [[Aberystwyth]] in October 2023, Rhun ap Iorwerth said the party was "not just for [[Welsh language|Welsh speakers]]".<ref>{{Cite news |date=2023-10-05 |title=Plaid Cymru not just for Welsh speakers - Rhun ap Iorwerth |language=en-GB |work=BBC News |url=https://www.bbc.com/news/uk-wales-politics-67012483 |access-date=2023-10-07}}</ref> Accomplishments like free school meals with the [[Second Drakeford government|Drakeford government]] were promoted.<ref>{{Cite news |date=2023-10-07 |title=Plaid Cymru must get free school meals credit - senior party figure |language=en-GB |work=BBC News |url=https://www.bbc.com/news/uk-wales-politics-67030669 |access-date=2023-10-07}}</ref>