From Joseph Persico’s interview on Booknotes:

“… what you're referring to is the fact that Sumner Welles, who was the undersecretary of State in the Roosevelt administration and who was an important figure, he was Roosevelt's man. The secretary of state was Cordell Hull, and Roosevelt pretty much circumvented him and--and worked through Sumner Welles, who was an old family friend. Welles had made some sexual advances on trains, part of his--his business trips, to black porters on these trains, who reported him. This was concealed for a long time. It was two or three years before it finally erupted. Roosevelt is under tremendous pressure from people who fear that having a man with homosexual tendencies in such a sensitive position at State--we have to remember we're not talking about the current world; we're talking about the attitudes of the--of the 1940s. He's looked upon as a--as a--a security threat, and Roosevelt very unhappily eventually dismisses Sumner Welles.“