Alarmed by President Roosevelt's plan to redistribute wealth from the rich to the poor, a group of millionaire businessmen, led by the Du Pont and J.P. Morgan empires, planned to overthrow Roosevelt with a military coup.
They envisioned an "army" of disgruntled World War I veterans, led by retired Marine Gen. Smedley D. Butler, as the force to topple the government. Butler was a colorful and outspoken champion of veterans' rights. But he was also their undoing.
After discovering the details of the conspiracy, the horrified general blew the whistle and brought the plot under the scrutiny of a congressional investigation.
Source: The Concise Columbia Electronic Encyclopedia