Dean's record in Vermont shows he is not too liberal to be elected. Here are press quotes from 2001.

"Howard Dean is Vermont's Harry Truman. Dean, like Truman, is a no-nonsense, plain-speaking guy who loves to give 'em hell. ... He defies labels, following a pragmatic not partisan path. ... Our first baby-boomer governor harkens to a time gone by, a time when families were strong and values deep. He is patriotic, a strong law and order man who believes in the American dream and expects people to do their best to climb the ladder."
The Associated Press - September 9, 2001 Column by Vermont Bureau Chief Christopher Graff

"This equal emphasis on creating jobs, balancing budgets and expanding government's social activism sums up Dean's approach to the office he has held longer than anyone in this century. A decade later, it's hard to think of another politician who could have handled the job so successfully for so long."
The Burlington Free Press (VT) - August 13, 2001