The conservative coalition, founded in 1937, was an unofficial alliance of members of the United States Congress which brought together the conservative wings of the Republican and Democratic parties to oppose President Franklin Delano Roosevelt's New Deal. In addition to Roosevelt, the conservative coalition dominated Congress for four presidencies, blocking legislation proposed by Roosevelt and his successors. By 1937, the conservatives were the largest faction in the Republican Party which had opposed the New Deal in some form since 1933. Despite Roosevelt being a Democrat himself, his party did not universally support the New Deal agenda in Congress. Democrats who opposed Roosevelt's policies tended to hold conservative views, and allied with conservative Republicans. These Democrats were mostly located in the South. According to James T. Patterson: "By and large the congressional conservatives agreed in opposing the spread of federal power and bureaucracy, in denouncing deficit spending, in criticizing industrial labor unions, and in excoriating most welfare programs. They sought to 'conserve' an America which they believed to have existed before 1933."
The coalition dominated Congress from 1937 to 1963, when former Senate Majority Leader Lyndon Johnson assumed the presidency and broke its influence. Johnson took advantage of weakened conservative opposition, and Congress passed many progressive economic and social reforms in his presidency. The conservative coalition, which controlled key congressional committees and made up a majority of both houses of Congress during Kennedy's presidency, had prevented the implementation of progressive reforms since the late 1930s. It remained a declining political force until it disappeared in the mid-1990s when few conservative Democrats remained in Congress. Following the 1994 Republican Revolution, many of the remaining conservative Democrats in congress joined to form the Blue Dog Coalition.
Never a formalized alliance, the conservative coalition, most often appeared on votes affecting labor unions based on Congressional roll call votes.