By 1855 the new party was well launched in the North. Anti-slavery Whigs such as William Seward and Thurlow Weed were dominant in the new grouping, but elements of the Know-Nothing movement, together with the Free-Soil party, abolitionists, and anti-Nebraska Democrats also supplied strength. The party's national organization was perfected at Pittsburgh in Feb., 1856, and its first presidential candidate, John C. Frémont, made a creditable showing against victorious James Buchanan. The party opposed the repeal of the Missouri Compromise and the extension of slavery, denounced the Supreme Court's decision in the Dred Scott Case, and favored the admission of Kansas as a free state.

Generally belligerent toward the South, the Republicans were regarded by Southerners with mingled hatred and fear as sectional tension increased. They were successful in the elections of 1858 and passed over their better-known leaders to nominate Abraham Lincoln in 1860. The party platform in 1860 included planks calling for a high protective tariff, free homesteads, and a transcontinental railroad; these were bids for support among Westerners, farmers, and eastern manufacturing interests.

Lincoln's victory over Stephen A. Douglas, John C. Breckinridge, and John Bell was the signal for the secession of the Southern states, and the Civil War followed. Union military failures early in the war and conservative opposition to such measures as the Emancipation Proclamation caused the party to lose ground in the Congressional elections of 1862. But despite mutterings against his leadership, Lincoln, renominated on the Union (Republican) ticket in 1864, defeated Gen. George B. McClellan.

Although a separate ticket headed by the radical Frémont withdrew before the election in 1864, the cleavage within the party between radicals and moderates widened as the war progressed. Radicals such as Benjamin F. Wade, Henry W. Davis, Thaddeus Stevens, Charles Sumner, and Edwin M. Stanton advocated a punitive policy for the South, while Lincoln and the moderates were inclined to leniency. The division was made complete when, after Lincoln's assassination, his successor, Andrew Johnson, adopted a moderate program of Reconstruction. Johnson, a Jacksonian Democrat from Tennessee, had been added to the ticket in 1864 to strengthen the idea of a Union party. Ultimately his policies and attempts to implement them antagonized his supporters among the moderate Republicans and paved the way for the triumph of the radicals in the congressional elections of 1866. The height of radical power was reached in 1868 with the impeachment of Johnson, which was defeated by only a one-vote margin.

The nomination of the war hero Ulysses S. Grant assured Republican success over the Democrats led by Horatio Seymour in the presidential election of 1868. The radicals were supreme under Grant, but their excesses and the open scandals of the administration created a new schism, leading to the formation of the Liberal Republican party. Its candidate, Horace Greeley, although supported by the Democrats, was not popular enough to defeat Grant in 1872, and corruption became even more widespread.

The election of 1876 indicated that radical Republicanism had lost much of its popular support. The Democratic candidate, Samuel J. Tilden, received a popular plurality of over 250,000 votes, but the disputed electoral votes of Florida, South Carolina, and Louisiana, the only Southern states still under Republican control, were awarded to Rutherford B. Hayes, and the Republican was declared President-elect. With the election, however, Republican domination of the South and radical rule of the party were definitely ended.

In the period that followed, the two parties differed little in their programs. Each party had numerous almost irreconcilable factions, and each avoided taking any real stand on controversial issues, which were generally left to lesser political groups such as the Granger movement and the Greenback party. The Republicans favored a protective tariff and the Democrats a tariff for revenue only, but even this traditional distinction was not rigidly kept. However, the Republican tariff policy was the work of leaders of the new industrial capitalism, whose influence in party councils began to be strongly felt under Grant.

The Republican "old guard," led by Roscoe Conkling, while failing to secure a third nomination for Grant in 1880, nevertheless temporarily blocked the presidential aspirations of James G. Blaine. Another ex-Union general, James A. Garfield, was nominated and was elected over a Democratic general, Winfield S. Hancock. Assassinated shortly after taking office, Garfield was succeeded by Vice President Chester A. Arthur.

In these postwar elections, the party, always supported by the Grand Army of the Republic, denounced all Democrats as former Copperheads and claimed to have alone saved the Union. But "waving the bloody shirt," as this type of propaganda was styled, was not enough to elect Blaine in 1884. The reform wing of the party, led by Carl Schurz, deserted Blaine for the conservative Democrat Grover Cleveland, who was elected. This defection by the mugwumps illustrated the lack of real issues between the two parties; it was the man and not the party that counted. Benjamin Harrison defeated Cleveland in 1888 but lost to him in 1892. The growing Populist party, with its radical program, had a peculiar position in those elections, receiving in each section of the country the support of the party not in power.

When, in 1896, the Democratic party was captured by the radicals under William Jennings Bryan, its presidential candidate in 1896, 1900, and 1908, the Republican party became openly the champion of the gold standard and conservative economic doctrines. The conservatives, skillfully guided by national chairman Marcus A. Hanna, won with William McKinley in 1896 and 1900, and under such leaders as Nelson W. Aldrich, Thomas B. Reed, Joseph G. Cannon, Thomas C. Platt, and Matthew S. Quay, the party prospered. Theodore Roosevelt, successor to the assassinated McKinley, easily defeated the conservative Democrat Alton B. Parker in 1904, and the vigorous foreign policy of his administration fostered the belief that the Republicans stood for the imperialism represented by the recent Spanish-American War.

Under Roosevelt's Republican successor and friend, William Howard Taft, "dollar diplomacy" flourished, but a new rift appeared in the party. Insurgents led by Senator Robert M. La Follette balked at the party's conservatism and when the regulars renominated Taft in 1912, most of the dissidents withdrew and in the Bull Moose convention chose Roosevelt to lead the new Progressive party ticket. Because of this division, the Democratic candidate, Woodrow Wilson, was elected President and, narrowly reelected in 1916 over Charles Evans Hughes, he served through World War I. The party, however, won the Congressional elections of 1918, and Republican opposition was a large factor in defeating Wilson's peace program. By straddling the issue of the League of Nations and calling for a return to "normalcy," the party easily elected Warren G. Harding in 1920. His administration rivaled Grant's for corruption, but after Harding died in office, his successor, Calvin Coolidge, was returned over John W. Davis and La Follette.

The Republican victory with Herbert C. Hoover in 1928 marked the first time since the end of Reconstruction that the party had carried states of the old Confederacy; this came about chiefly because the Democratic candidate, Alfred E. Smith, was a Roman Catholic and an opponent of prohibition. Hoover and the Republicans were blamed for the disastrous economic depression that soon enveloped the country, and the Democrats, under Franklin Delano Roosevelt, were swept into office in 1932. The frustrated Republicans were never able to break the remarkable hold of Roosevelt and the New Deal on the electorate and regularly went down to defeat every four years, with Alfred M. Landon (1936), Wendell Willkie (1940), and Thomas E. Dewey (1944).

Isolationists held the upper hand in the party before World War II, and in 1940 two Republicans, Henry L. Stimson and Frank Knox, were virtually read out of the party for accepting posts in Roosevelt's cabinet. But the party supported the nation's war effort and after the war, led by Senator Arthur H. Vandenberg, joined the Democratic administration in a bipartisan foreign policy. In 1948 the Republican party was supremely confident of defeating Roosevelt's successor, Harry S. Truman. However, Dewey, the party's first unsuccessful candidate ever to be renominated, was defeated by a close margin.

In 1952, the more liberal element among the Republicans was able to deny the conservatives' choice, Robert A. Taft, choosing instead the popular war hero, Gen. Dwight D. Eisenhower as their presidential nominee. Campaigning against the domestic policy of the Truman administration and its prosecution of the war in Korea, Eisenhower swept to a landslide victory over the Democratic candidate, Adlai E. Stevenson. The domestic program of the Eisenhower adminstration was moderately conservative, and in foreign policy the internationalist approach of the previous Democratic administration was continued. Despite the President's overwhelming personal popularity and his landslide reelection over Stevenson in 1956, a feat that included carrying several Southern states for the second consecutive time, the Democrats retained control of Congress through the 1960 elections.

In 1960, an incumbent Vice President, Richard M. Nixon was nominated for president for the first time since 1836. Although the Republican party had become a minority in registration, Nixon failed by fewer than 200,000 votes to defeat John F. Kennedy. In 1964 the conservative wing of the party engineered the nomination of Senator Barry Goldwater, who was, however, defeated in a landslide by Lyndon B. Johnson. In 1968 the party rebounded and won a narrow victory with party stalwart Richard Nixon over Democratic candidate Hubert Humphrey, who was handicapped by disaffection over the Vietnam War. In 1972, President Nixon was triumphantly reelected, defeating George McGovern on a record of favoring a strong defense with a limited détente with the Soviet Union and China, and a conservative domestic program featuring a decentralization of political power.

The party, however, suffered a series of massive setbacks with the resignation of Vice President Spiro Agnew upon his conviction for tax evasion and revelations of major White House involvement in the Watergate affair, which led finally to the resignation of President Nixon. Nixon's successor, Gerald R. Ford, attempted to disassociate the party from the scandals, but Watergate appeared to be a major factor in the substantial Republican losses in the 1974 elections and in the subsequent defeat of Ford by the Democrat Jimmy Carter.

In 1980, the conservative Ronald Reagan, a former supporter of Barry Goldwater, regained the presidency for the Republicans and reversed long-standing political trends by instituting a supply-side economic program of budget and tax cuts. He also advocated increased military spending and presided over the largest military buildup during peacetime in American history. The Iran-contra affair, which broke in late 1986, marred the last years of his tenure, though his vice-president, George H. W. Bush, was nonetheless able to defeat the Democratic nominee, Michael Dukakis, in the 1988 election.

Bush was generally recognized as strong on foreign policy. He was widely lauded for his role in orchestrating the coalition of forces against Iraq in the Persian Gulf War. He also largely continued Reagan's policy toward the Soviet Union. On the domestic side, however, Bush's administration was perceived as being slow to respond to such problems as stagnant economic growth, rising unemployment, and the unaffordability of health care for many Americans. Bush's high popularity after the Persian Gulf War dropped rapidly, and he lost the 1992 presidential election to the Democrat, Arkansas's Governor Bill Clinton.

In the 1994 congressional and state elections, however, the Republican party scored major victories and increased its hold in the South. Republicans unseated long-time Democratic incumbents, winning control of both houses of Congress (for the first time since the 1950s) and claiming several governorships. Newt Gingrich, who spearheaded the Republicans' congressional election campaign with his conservative "Contract with America" program, became speaker of the House. While bills were passed on the key program components, many items were thwarted or defeated in Congress or by the president.

The 1996 elections saw incumbents generally retain their offices. Former Senate majority leader Bob Dole won the Republican nomination for the presidency, but he and his running mate, Jack Kemp, were never able to reduce significantly President Clinton's substantial lead. In the House and Senate, Republicans retained their majorities, slightly diminished in the former and slightly increased in the latter. The 1998 mid-term elections saw the Republican margin in the House reduced, despite expectations that they would benefit from the effects of the Lewinsky scandal; the results led to Gingrich's resignation from office.

In the 2000 elections, the party's presidential nominee, George W. Bush appeared generally to lead in the polls in what ultimately became a popular-vote loss to Democrat Al Gore. Despite not winning the popular vote. Bush secured the presidency with a victory in the electoral college when he won Florida by an extremely narrow margin and outlasted Gore's unsuccessful court challenge of the Florida vote-counting process. The party did not fair as well in other races for national office, and the Democrats made gains in Congress, although the Republicans retained control there.

The party lost control of the Senate as a result of a defection in mid-2001, but regained it after the Nov., 2002, elections. In 2004, Bush was renominated without opposition, and he subsequently soundly defeated the Democratic nominee, John Kerry. The Republicans also increased their majorities in both houses of Congress, as retiring Senate Democrats from the South were replaced by Republicans. Public discontent with congressional scandals and the war in Iraq led to reversals in the congressional elections of 2006, however, and the party lost control of both houses of Congress, albeit narrowly in the Senate.

See H. L. Trefousse, The Radical Republicans (1968); E. Foner, Free Soil, Free Labor, Free Men (1970); F. L. Burdette, The Republican Party (2d ed. 1972); E. Lindop, All about Republicans (1985); W. Gienapp, The Origins of the Republican Party, 1852–56 (1988); F. Schwengel, The Republican Party (1988); L. L. Gould, Grand Old Party: A History of the Republicans (2003).