The biggest conflict between the UMW and the government was while Franklin Roosevelt was president of the United States and John L. Lewis was president of the UMW. Originally, the two worked together well, but, after the 1937 strike of United Automobile Workers against General Motors, Lewis stopped trusting Roosevelt, claiming that Roosevelt had gone back on his word. This conflict led Lewis to resign as CIO president. Roosevelt repeatedly won large majorities of the union votes, even in 1940 when Lewis took an isolationist position on Europe, as demanded by far-left union elements. Lewis denounced Roosevelt as a power-hungry war monger, and endorsed Republican Wendell Willkie.