Sure they have. It's called Jimmy Carter, Bill Clinton, Lyndon Johnson, Trent Lott, and on and on.
All the ones you have named are sell-outs, turncoats and unreliable, characterless people to one degree or another. There are no R.E. Lees, Forresters, or S.W. Jacksons in that crowd.
As opposed to the Kennedys (ALL of 'em), Barney Frank, FDR, Truman, Schumer, Wellstone, and on and on.
IOW, nearly all politicians, no matter whence they hail, are scumbags. That's not what I was referring to........but you knew that.