Warren Gamaliel Harding (November 2, 1865 – August 2, 1923) was the 29th president of the United States from 1921 until his death in 1923. A major foreign policy achievement came with the Washington Naval Conference of 1921–1922, in which the world's major naval powers agreed on a naval limitations program that lasted a decade. Harding released political prisoners who had been arrested for their opposition to World War I. The Senate debated Versailles in September 1919, and Harding made a major speech against it. By then, Wilson had suffered a stroke while on a speaking tour. With an incapacitated president in the White House and less support in the country, the treaty was defeated. Harding's Socialist opponent in the 1920 election, Eugene Debs, was serving a ten-year sentence in the Atlanta Penitentiary for speaking against the war. Wilson had refused to pardon him before leaving office. At Harding's request, Debs visited the president at the White House before going home to Indiana.