Republican Party (United States)
Founded in 1854, the GOP originally subscribed to classical liberalism and took ideological stands that were anti-slavery and pro-economic reform. Abraham Lincoln was the first Republican president in the history of the United States. The party was usually dominant over the Democrats during the Third Party System and Fourth Party System. In 1912, Theodore Roosevelt formed the Progressive ("Bull Moose") Party after being rejected by the GOP and ran as a third-party presidential candidate. Roosevelt called for many social reforms, some of which were later championed by New Deal Democrats in the 1930s. He lost the 1912 election, and when most of his supporters returned to the GOP, they were at odds with the party's new conservative economic stance; many left for the Democratic Party, and an ideological shift to the right occurred in the Republican Party. Later in the 20th century, the liberal Republican element was overwhelmed by a conservative surge begun by Barry Goldwater in 1964 and continued during the Reagan Era.
Unionist Party (United States)
By 1860, the Whig Party was defunct. A group of former Whigs formed the Constitutional Union Party, with John Bell as candidate for President. Also as in 1850, ex-Whigs and anti-secession Democrats combined as "Unionists" to oppose secessionists in state elections, especially in Kentucky, Maryland, Missouri and Virginia, where the Republican Party label was still toxic. Bell's candidacy was ineffective, but the state strategy proved successful as the American Civil War began in 1861.