In 1921, newly elected president Warren G. Harding chose Mellon as his Secretary of the Treasury. Mellon would remain in office until 1932, serving under Harding, Calvin Coolidge, and Herbert Hoover, all three of whom were members of the Republican Party. Mellon sought to reform federal taxation in the aftermath of World War I, cutting taxes on top earners but leaving in place a progressive income tax. Some of Mellon's proposals were enacted by the Revenue Act of 1921 and the Revenue Act of 1924, but it was not until the passage of the Revenue Act of 1926 that the "Mellon plan" was fully realized. He also presided over a reduction in the national debt, which dropped substantially in the 1920s. Mellon's influence in state and national politics reached its zenith during Coolidge's presidency. Journalist William Allen White noted that "so completely did Andrew Mellon dominate the White House in the days when the Coolidge administration was at its zenith that it would be fair to call the administration the reign of Coolidge and Mellon."