Editing Plaid Cymru (section)

====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>