After the outbreak of World War I, he became the head of the Commission for Relief in Belgium, an international relief organization that provided food to occupied Belgium. When the U.S. entered the war, President Woodrow Wilson appointed Hoover to lead the Food Administration, and Hoover became known as the country's 'food czar'. Hoover was extremely unpopular when he left office after the 1932 election, and his historical reputation would not begin to recover until the 1970s. Despite his national renown, Hoover's service in the Wilson administration had alienated farmers and the conservative Old Guard of the GOP, and his presidential candidacy fizzled out after his defeat in the California primary by favorite son Hiram Johnson. At the 1920 Republican National Convention, Warren G. Harding emerged as a compromise candidate after the convention became deadlocked between supporters of Johnson, Leonard Wood, and Frank Orren Lowden. Hoover backed Harding's successful campaign in the general election, and he began laying the groundwork for a future presidential run by building up a base of strong supporters in the Republican Party.