Origins of the American Civil War
In almost every northern state, organizers attempted to have a Republican Party or an anti-Nebraska fusion movement on ballots in 1854. In areas where the radical Republicans controlled the new organization, the comprehensive radical program became the party policy. Just as they helped organize the Republican Party in the summer of 1854, the radicals played an important role in the national organization of the party in 1856. Republican conventions in New York, Massachusetts, and Illinois adopted radical platforms. These radical platforms in such states as Wisconsin, Michigan, Maine, and Vermont usually called for the divorce of the government from slavery, the repeal of the Fugitive Slave Laws, and no more slave states, as did platforms in Pennsylvania, Minnesota, and Massachusetts when radical influence was high.
United States
The United States has operated under a two-party system for most of its history. For elective offices at most levels, state-administered primary elections choose the major party nominees for subsequent general elections. Since the general election of 1856, the major parties have been the Democratic Party, founded in 1824, and the Republican Party, founded in 1854. Since the Civil War, only one third-party presidential candidate—former president Theodore Roosevelt, running as a Progressive in 1912—has won as much as 20% of the popular vote. The President and Vice-president are elected through the Electoral College system.