The Republican Party, also known as the GOP ("Grand Old Party"), is one of the two major contemporary political parties in the United States. It is a big tent of competing and often opposing viewpoints, but modern American conservatism, a synthesis of classical liberalism and conservatism, is the party's majority ideology. It also has notable libertarian, populist, and centrist factions in Congress. The Republican Party emerged as the main political rival of the Democratic Party in the mid-1850s, and the two parties have dominated American politics ever since.
Northern members of the conservative Whig Party are considered the ideological and historical predecessors of the Republican Party. The GOP was founded in 1854 by anti-slavery activists who opposed the Kansas–Nebraska Act, which allowed for the potential expansion of chattel slavery into the western territories. Upon its founding, it supported classical liberalism and economic reform while opposing the expansion of slavery. It initially had a very limited presence in the South, but was very successful in the North; by 1858, it had enlisted former Whigs and former Free Soil Democrats to form majorities in nearly every state in New England. The Republican Party did not openly oppose slavery in the Southern states prior to the American Civil War, stating that it opposed the spread of slavery into the Western territories or into the Northern states; however, the Party was sympathetic to the abolitionist cause.
Seeing a future threat to the practice of slavery with the 1860 election of Abraham Lincoln, the first Republican president, many states in the South seceded from the nation and joined the Confederacy. Under the leadership of Lincoln and a Republican Congress, the Republican Party led the fight to destroy the Confederacy during the American Civil War, preserving the Union and abolishing slavery. After the victory of the Union in the Civil War, the party largely dominated the national political scene until 1932. The GOP lost its congressional majorities during the Great Depression when the Democrats' New Deal programs proved popular. Republican President Dwight D. Eisenhower presided over a period of economic prosperity after World War II. Republican President Richard Nixon carried 49 states in 1972 with his silent majority, but resigned from office in 1974 due to the Watergate scandal. The election of Republican President Ronald Reagan in 1980 realigned national politics, bringing together advocates of free-market economics, social conservatives, and Cold War foreign policy hawks under the Republican banner.
The Republican coalition comprises business interests, affluent voters, and religious traditionalists. While the party is a big tent, both Republican voters and politicians generally support social or economic conservatism, laissez-faire capitalism, deregulation, lower taxes, gun rights, restrictions on labor unions, and increased military spending. The Republican Party is a member of the International Democrat Union, an international alliance of centre-right political parties. It has several prominent political wings, including a student wing, the College Republicans; a women's wing, the National Federation of Republican Women; and an LGBT wing, the Log Cabin Republicans.