article: Third party (politics)
links: United States Republican Party Labour Party (UK) Scottish National Party Party for Socialism and Liberation United States Democratic Party American Independent Party Communist Party USA Alliance Party of Northern Ireland Sinn Féin Social Democratic and Labour Party Green Party of England and Wales United States People's Party (United States) Green Party of the United States Liberal Democrats (UK) Conservative Party (UK) Alliance Party (United States) British House of Commons Libertarian Party (United States) Plaid Cymru United Kingdom Democratic Unionist Party