The Pennsylvania gubernatorial race hasn't tightened, despite a summer of campaigning and a steady stream of television ads for both candidates.

A new Franklin & Marshall College poll shows incumbent Republican Gov. Tom Corbett is trailing his Democratic challenger Tom Wolf by 25 points.

Forty-nine percent of registered voters surveyed said they'd vote for the York County businessman, with 24 percent favoring Corbett. Responses among likely voters, said poll director Terry Madonna, showed no difference. Nor has the needle moved much since F&M's June poll.

"Nothing has changed in terms of policy successes, nothing has changed in terms of the dynamic of Gov. Corbett's leadership," Madonna said.

More voters still rank education as their top issue – a sore spot for the Corbett administration, which has been put on the defensive repeatedly about a drop in overall schools spending.

The barrage of television ads this summer hasn't moved the polls either, despite the more than 80 percent of respondents who said they'd seen ads for both candidates.

Corbett remains in uncharted territory, with fewer than half of Republican respondents saying he deserves re-election, and 24 percent of all respondents giving him a high job performance rating.

"No incumbent governor seeking re-election has been where Governor Corbett is situated," Madonna said. "No incumbent governor seeking re-election has had that low a job performance [rating]."

The poll of 520 registered Pennsylvania voters was conducted in mid-August and has a margin of error of plus or minus 4.3 percentage points.