He was also approached by some businessmen with connections to Dupont and JP morgan to overthrow FDR via military coup in 1933. He ended up turning them into congress. Gerald McGuire one of the conspirators was quoted in saying this:

“We need a fascist government in this country… to save the nation from the communists who want to tear it down and wreck all that we have built in America. The only men who have the patriotism to do it are the soldiers, and Smedley Butler is the ideal leader. He could organize a million men overnight.”

Communist/anarchist/socialist politics where popular amongst factory workers at the time.

This conspiracy was kept from the public for many years. In the late 60s some reporter dug it out of the congressional archives and did a story on it.