By Larry Kane

PHILADELPHIA (CBS) — With four weeks left until Election Day, the race for governor of Pennsylvania appears to be a runaway.

The latest Quinnipiac University poll shows a slight narrowing: Democratic challenger Tom Wolf leading incumbent Republican Tom Corbett now by just 17 points (55 percent to 38 percent), down from 20 points a month ago.

But in almost every demographic sampling, it appears that Corbett still has a mountain to climb.

Wolf has a huge lead among women (59 percent to 34 percent), a nine-point lead among independents (49 to 40) and, naturally, a large lead among Democrats.

Corbett leads big among Republicans (75 percent to 22 percent), but the pollsters say the 22-percent opposition in this race is one of the worst showings by a candidate with his own party in nine states they poll in.