Left: Richard Nixon; Right: Aldrich Ames

5. Richard Nixon
Richard Nixon could have been one of our more successful presidents (1969-1974). He is credited with getting American troops out of Vietnam and improving relations with both Russia and China. But during his second term, he became caught up in the infamous Watergate Scandal, when he lied to cover up Executive Branch involvement in a botched burglary against the Democratic Party Headquarters. He was forced to resign to avoid impeachment.