Although I believe that Carter was the last honest man to sit in the Oval Office
Well, then you believe wrongly. Carter's public image was one of the most artificially crafted of all the recent Presidents. As anyone who worked on his staff, or especially the White House staff, and the Secret Service, and they will tell you that he was nothing like the man on TV, and often outright lied about what he was doing in the White House.
For instance, in a cheap stunt to win the White House and embarrass the Fords, Carter often claimed during the 76 campaign that "there would be no alcohol in his White House", a reference to Betty Ford's notorious problem with the bottle. Dozens of people have claimed, afterwords, that while no alcohol was served at state functions, the Carter's themselves drank often.
