Editing Political party (section)

===Two-party systems===
{{Main|Two-party system}}
In several countries, there are only two parties that have a realistic chance of competing to form government.<ref>{{cite book |author1=Arend Lijphart |author1-link=Arend Lijphart |author2=Don Aitkin |author2-link=Don Aitkin |year=1994 |title=Electoral Systems and Party Systems: A Study of Twenty-seven Democracies, 1945–1990 |publisher=Oxford University Press |page=67 |isbn=978-0198280545}}</ref> One current example of a two-party system is the [[United States]], where the national government has for much of the country's history exclusively been controlled by either the [[Democratic Party (United States)|Democratic Party]] or the [[Republican Party (United States)|Republican Party]].<ref>{{cite web |url=https://theconversation.com/the-two-party-system-is-here-to-stay-132423 |title=The two-party system is here to stay |first=Alexander |last=Cohen |publisher=The Conversation |date=2 March 2020 |access-date=22 January 2021 |archive-date=14 January 2021 |archive-url=https://web.archive.org/web/20210114220626/https://theconversation.com/the-two-party-system-is-here-to-stay-132423 |url-status=live }}</ref> Other examples of countries which have had long periods of two-party dominance include [[Colombia]], [[Uruguay]],<ref name=coppedge98>{{cite journal |first=Michael |last=Coppedge |title=The Dynamic Diversity of Latin American Party Systems |journal=Party Politics |volume=4 |issue=4 |pages=547–568 |date=1 October 1998 |doi=10.1177/1354068898004004007|s2cid=3276149 }}</ref> [[Malta]],<ref>{{cite journal |first=Michelle |last=Cini |title=A Divided Nation: Polarization and the Two-Party System in Malta |journal=South European Society and Politics |volume=7 |issue=1 |pages=6–23 |date=2 December 2009 |doi=10.1080/714004966|s2cid=154269904 }}</ref> and [[Ghana]].<ref>{{cite journal |author1=Minion K. C. Morrison |author1-link=Minion K. C.  Morrison |author2=Jae Woo Hong |title=Ghana's political parties: How ethno/regional variations sustain the national two-party system |journal=The Journal of Modern African Studies |volume=44 |issue=4 |pages=623–647 |date=December 2006 |doi=10.1017/S0022278X06002114|s2cid=154384854 }}</ref> Two-party systems are not limited to democracies; they may be present in authoritarian regimes as well. Competition between two parties has occurred in historical autocratic regimes in countries including [[Brazil]]<ref>{{cite journal |author1=James Loxton |author2=Timothy Power |title=Introducing authoritarian diasporas: causes and consequences of authoritarian elite dispersion |journal=Democratization |volume=28 |issue=3 |date=2 June 2020 |pages=465–483 |doi=10.1080/13510347.2020.1866553|s2cid=232245480 |url=https://ora.ox.ac.uk/objects/uuid:316c1c11-6113-4b39-97f6-b7a3d35040b1 }}</ref> and [[Venezuela]].<ref>{{cite journal |first=Miriam |last=Kornblith |title=Latin America's Authoritarian Drift: Chavismo After Chávez? |journal=Journal of Democracy |volume=24 |issue=3 |pages=47–61 |date=July 2013 |doi=10.1353/jod.2013.0050|s2cid=36800728 }}</ref>

A democracy's political institutions can shape the number of parties that it has. In the 1950s Maurice Duverger observed that single-member district single-vote plurality-rule elections tend to produce two-party systems,<ref name=duverger64/>{{rp|217}} and this phenomenon came to be known as [[Duverger's law]]. Whether or not this pattern is true has been heavily debated over the last several decades.<ref>{{cite journal |author1=William Roberts Clark |author2=Matt Golder |title=Rehabilitating Duverger's Theory: Testing the Mechanical and Strategic Modifying Effects of Electoral Laws |journal=Comparative Political Studies |volume=39 |issue=6 |pages=679–708 |date=August 2006 |doi=10.1177/0010414005278420|s2cid=154525800 }}</ref> Some political scientists have broadened this idea to argue that more restrictive political institutions (of which [[first past the post]] is one example) tend to produce a smaller number of political parties, so that extremely small parties systems – like those with only two parties – tend to form in countries with very restrictive rules.<ref>{{cite journal |first1=Karen E. |last1=Ferree |first2=G. Bingham |last2=Powell |first3=Ethan |last3=Scheiner |title=Context, Electoral Rules, and Party Systems |journal=Annual Review of Political Science |volume=17 |pages=421–439 |date=May 2014 |doi=10.1146/annurev-polisci-102512-195419|doi-access=free }}</ref>

Two-party systems have attracted heavy criticism for limiting the choices that electors have, and much of this criticism has centered around their association with restrictive political institutions. For example, some commentators argue that political institutions in prominent two-party systems like the United States have been specifically designed to ensure that no third party can become competitive.<ref>{{cite news |url=https://www.washingtonpost.com/news/the-fix/wp/2016/04/27/why-are-there-only-two-parties-in-american-politics/ |title=Why are there only two parties in American politics? |newspaper=[[The Washington Post]] |first=Aaron |last=Blake |date=27 April 2016 |access-date=17 September 2021}}</ref> Criticisms also center around these systems' tendencies to encourage [[insincere voting]] and to facilitate the [[Vote splitting#Spoiler effect and center-squeeze effect|spoiler effect]].<ref>{{cite book |first1=Lisa Jane |last1=Disch |first2=Robert Y. |last2=Shapiro |year=2002 |title=The Tyranny of the Two-Party System |publisher=Columbia University Press |isbn=978-0231110358}}</ref>{{rp|ch. 1}}