First ones that come to my mind are Gary Hart & Ted Kennedy, either of whom could have been a Rat nominee.
I actually had a front row seat to the Gary Hart self-destruction. My wife and I were on our honeymoon and at a NYC hotel the day the scandal broke. Gary Hart did a press conference literally outside the hotel I was staying at. I remember us looking at the window down at Gary Hart with all the cameras on him and then having CNN on in the room and seeing the same scene on TV. We then went and saw CATS at the Winter Garden that night.