I think there are similarities
Both won thanks to a sense among their constituents of :
"He may be a crook, but he's our crook!"
And from a desire to poke a stick in someone's eye with a vote.
Palin is a very popular governor. I doubt many Alaskans appreciated how she was treated when she had the temerity to venture down into the Lower 48.
How did Murtha get re-elected after calling his constituents racists and rednecks? That surprised me as well.