Reply #4: He's a strong incumbent

[Kber]

from CNN Political Tickler

Saltonstall admits that defeating a sitting member of Congress will not be easy. Stupak was first elected to Congress in 1992, and has won by double digits in five out of nine campaigns according to the Almanac of American Politics. He easily defeated his most recent primary challenger during the 2000 election by a whopping 89-11 margin.

"As a realist I know that defeating an incumbent is difficult," Saltonstall explained. "But I also know that there are many past supporters who have told me they have voted for Bart in every single election and they'll never vote for him again. It will be a lot of hard work, it will be a serious challenge, but we're going to try because the voters of this district deserve a choice."

http://politicalticker.blogs.cnn.com/2010/03/10/stupak-facing-primary-challenger-over-abortion-funding/?fbid=j0gCXXbOoTh#comment-3306025

But he's pissed a lot of people off and I think Connie could get some real traction.