leaders considered Dewey to be too young (at 38, just three years above the minimum age required by the US Constitution) and too inexperienced to lead the nation in wartime. Furthermore, Dewey's non-interventionist stance became problematic when Germany quickly conquered France, and seemed poised to invade Britain. As a result, at the 1940 Republican National Convention many delegates switched from Dewey to Wendell Willkie, who was a decade older and supported aid to the Allies fighting Germany. Dewey led on the first ballot, but was well below the vote total he needed to win. He steadily lost strength to Willkie in succeeding ballots, and Willkie was nominated on the convention's sixth ballot. Willkie lost to Franklin D. Roosevelt in the general election. 1944 Dewey's foreign-policy position evolved during the 1940s; by 1944 he was considered an internationalist and a supporter of projects such as the United Nations. It was in 1940 that Dewey first clashed with Robert A. Taft. Taft—who maintained his non-interventionist views and economic conservatism to his death—became Dewey's great rival for control of the Republican Party in the 1940s and early 1950s. Dewey became the leader of moderate Republicans, who were based in the Eastern states, while Taft became the leader of conservative Republicans who dominated most of the Midwest. Dewey was the frontrunner for the 1944 Republican nomination. In April 1944 he won the key Wisconsin primary, where he defeated Wendell Willkie and former Minnesota governor Harold Stassen. Willkie's poor showing in Wisconsin forced him to quit the race and he died later that year. At the 1944 Republican Convention, Dewey's chief rivals—Stassen and Ohio governor John W. Bricker—both withdrew and Dewey was nominated almost unanimously. Dewey then made Bricker (who was supported by Taft) his running mate. This made Dewey the first presidential candidate to be born in the 20th century. As of 2021, he was also the youngest Republican presidential nominee. In the general election campaign, Dewey crusaded against the alleged inefficiencies, corruption and Communist influences in incumbent president Roosevelt's New Deal programs, but mostly avoided military and foreign policy debates. Dewey had considered including the conspiracy theory that Roosevelt knew about the attack on Pearl Harbor beforehand and allowed it to happen and to say: "...and instead of being re-elected he should be impeached." The allegation would have suggested the then-secret fact that the U.S. had broken the Purple code still in use