Here's another document from the Westbrook Pegler papers at the Herbert Hoover Library in North Branch, Iowa.
It's a 1949 letter between two conservative (some would say ultra-conservative) journalists, John T. Flynn, author of The Roosevelt Myth (available free online) and Westbrook Pegler, who later "went off he deep end" writing for the John Birch Society.
The letter clearly reflects that both Flynn and Pegler knew the truth of Roosevelt/Mercer affair (as did Walter Trohan as previosly posted on this blog) whereupon Flynn lays out his philosophy as to why the information should not be released. It was not until 1966 that Jonathan Daniels finally came clean with the story that 0thers had been keeping quiet for over a decade and a half.
The letter also contain a bitter attack on the Roosevelt morality, frankly inferring that "the apple doesn't fall far from the tree".