The Plot against FDR

An email brings a link to a radio program at the BBC on an attempted coup during the Roosevelt presidency:

The Whitehouse Coup, BBC: Document uncovers details of a planned coup in the USA in 1933 by right-wing American businessmen  The coup was aimed at toppling President Franklin D Roosevelt with the help of half-a-million war veterans. The plotters, who were alleged to involve some of the most famous families in America, (owners of Heinz, Birds Eye, Goodtea, Maxwell Hse & George Bush’s Grandfather, Prescott) believed that their country should adopt the policies of Hitler and Mussolini to beat the great depression. Mike Thomson investigates why so little is known about this biggest ever peacetime threat to American democracy. [Listen to this programme in full] [View a picture gallery of images related to this edition]

I'm not overly familiar with this episode, so here's what Wikipedia has to say:

Business Plot, Wikipedia: The Business Plot, The Plot Against FDR, or The White House Putsch, was an uncovered conspiracy involving several wealthy businessmen to overthrow President Franklin D. Roosevelt in 1933.

Purported details of the matter came to light when retired Marine Corps Major General Smedley Butler testified before a Congressional committee that a group of men had attempted to recruit him to serve as the leader of a plot and to assume and wield power once the coup was successful. Butler testified before the McCormack-Dickstein Committee in 1934. In his testimony, Butler claimed that a group of several men had approached him as part of a plot to overthrow Roosevelt in a military coup. One of the alleged plotters, Gerald MacGuire, vehemently denied any such plot. In their final report, the Congressional committee supported Butler's allegations on the existence of the plot, but no prosecutions or further investigations followed, and the matter was mostly forgotten.

General Butler claimed that the American Liberty League was the primary means of funding the plot. The main backers were the Du Pont family, as well as leaders of U.S. Steel, General Motors, Standard Oil, Chase National Bank, and Goodyear Tire and Rubber Company. A BBC documentary claims Prescott Bush, father and grandfather to the 41st and 43rd US Presidents respectively, was also involved. ...

Partial corroboration of Butler's story

Portions of Butler's story were corroborated by:

• Veterans of Foreign Wars commander James E. Van Zandt. "Less than two months" after General Butler warned him, he said "he had been approached by 'agents of Wall Street' to lead a Fascist dictatorship in the United States under the guise of a 'Veterans Organization.' "
• Captain Samuel Glazier—testifying under oath about plans of a plot to install a dictatorship in the United States.
• Reporter Paul Comly French, reporter for the Philadelphia Record and the New York Evening Post.

...Historical treatment

Several scenarios have been proposed in explaining why the affair did not become a cause celebre, among which are:

• The story was an embarrassment to people of influence, and it was best to sweep it under the rug as quickly as possible.
• In 1934, newspapers were controlled by a relatively small elite — according to then-Interior Secretary Harold L. Ickes, 82% of all dailies had monopolies in their communities. Proponents of the theory thus suggest that the media downplayed Butler's testimony based on the interests of their advertisers and owners.
• Some of Roosevelt's advisors were in on the plot, and downplayed it when it was exposed to prevent their dirty laundry from being aired in public.

Those who doubt Butler's testimony claim that it simply lacked evidence.

• Historian Robert F. Burk: "At their core, the accusations probably consisted of a mixture of actual attempts at influence peddling by a small core of financiers with ties to veterans organizations and the self-serving accusations of Butler against the enemies of his pacifist and populist causes."
• Historian Hans Schmidt: "Even if Butler was telling the truth, as there seems little reason to doubt, there remains the unfathomable problem of MacGuire's motives and veracity. He may have been working both ends against the middle, as Butler at one point suspected. In any case, MacGuire emerged from the HUAC hearings as an inconsequential trickster whose base dealings could not possibly be taken alone as verifying such a momentous undertaking. If he was acting as an intermediary in a genuine probe, or as agent provocateur sent to fool Butler, his employers were at least clever enough to keep their distance and see to it that he self-destructed on the witness stand...MacGuire repeatedly perjured himself...Butler may have blown the whistle on an incipient conspiracy..."
• Historian Arthur M. Schlesinger Jr.: "Most people agreed with Mayor La Guardia of New York in dismissing it as a "cocktail putsch... As for the House committee, headed by John McCormack of Massachusetts, it declared itself "able to verify all the pertinent statements made by General Butler" except for MacGuire's direct proposal to him, and it considered this more or less confirmed by MacGuire's European reports. No doubt MacGuire did have some wild scheme in mind, though the gap between contemplation and execution was considerable and it can hardly be supposed that the republic was in much danger."
• Historian James E. Sargent reviewing "The Plot to Seize the White House" by Jules Archer: "Thus, Butler (and Archer) assumed that the existence of a financially backed plot meant that fascism was imminent and that the planners represented a wide spread and coherent group, having both the intent and the capacity to execute their ideas. So when his testimony was criticized and even ridiculed in the media and ignored in Washington, Butler saw (and Archer sees) conspiracy everywhere. Instead, it is plausible to conclude that the honest and straightforward, but intellectually and politically unsophisticated, Butler perceived in simplistic terms what were in fact complex trends and events. Thus he leaped to the simplistic conclusion that the President and the Republic were in mortal danger. In essence, Archer swallowed his hero whole."

If you know more about this, I'd be interesting in learning more.