The Democratic Party is one of the two major contemporary political parties in the United States. Since the 1850s, its main political rival has been the Republican Party; the two parties have since dominated American politics. The Democratic Party was founded in 1828. Martin Van Buren of New York played the central role in building the coalition of state organizations that formed a new party as a vehicle to elect Andrew Jackson of Tennessee. The Democratic Party is the world's oldest active political party.

By the mid-20th century it had undergone a dramatic ideological realignment and reinvented itself as a party supporting organized labor, the civil rights of minorities, and progressive reform. The Democratic Party at its inception was against central government power (including abolishing the Bank of the United States) as its key platform. It was not sympathetic to native Americans and opposed the abolition of slavery. In the run up to the Civil War, the party became sharply divided between Northern and Southern Democrats, the former believing US territories should vote on whether or not to allow slavery within their borders and the latter believing slavery should be allowed regardless.