Despite campaign stops and a flood of negative television ads against his challenger, Gov. Tom Corbett has not improved his standing with Pennsylvania voters, the latest poll shows.

Democratic candidate Tom Wolf has a 25-point lead over of the incumbent, according to the Franklin & Marshall College Poll released Thursday.

The results show 49 percent of polled Pennsylvanians would vote for the York County businessman, while 24 percent would support Corbett and 25 percent are undecided. That's similar to the same poll's June results, in which 47 percent chose Wolf and 25 percent chose Corbett.

"Nothing much has changed this summer. Corbett has not given voters a reason to choose him, and he's not managed to beat up Tom Wolf," said Terry Madonna, director of the poll and the college's Center for Politics and Public Affairs.


In the last few months, Corbett has had "no legislative accomplishments" and has set "no new arguments," Madonna said.

"And those anti-Wolf ads are not resonating with voters," he said.

Voters everywhere are weary of negative politics, Madonna said.

"Wolf comes off as unpolitical, upbeat and positive," which is resonating with voters, he said.

Reaction: The Corbett campaign denounced the Franklin & Marshall.

"We're going to take this poll with a grain of salt," said Chris Pack, spokesman for the Republican's campaign.

The poll assumes a 12-point turnout advantage for Democrats on Election Day, and polls many individuals who don't regularly show up, he said.


"Even in one of their best years in 2006, Democrats had a five-point advantage at the polls," Pack said.

Democrats had a three-point advantage on Election Day when Corbett was elected in 2010, which he said is a more likely turnout model this year.

"(The Franklin & Marshall) poll not only completely ignores that model, but skews outright to Democrats," Pack said.

In June, Wolf held a 20-point lead over Corbett in the Quinnipiac University poll. The Rasmussen Reports survey also showed a 20-point lead in Wolf's favor.

Looking ahead: The race will likely tighten a little this fall, Madonna said.

But Corbett faces "the biggest uphill challenge of any incumbent governor seeking re-election in modern history," he said.

"If he can't find something to damage Wolf politically, he's going to have to give Pennsylvanians a reason to vote for him for a second term," Madonna said.

Some of Corbett's television ads have accused Wolf of using a Delaware registration to avoid paying corporate taxes in Pennsylvania.

Those ads "aren't playing with voters," Madonna said.

Pennsylvanians rank education as the most important issue when considering who to elect governor, according to the poll.

Wolf's team has repeatedly said he will restore Corbett's in cuts to public education and extend state education to include universal pre-K.

"After four years of Gov. Corbett's failures on education and the economy, Pennsylvanians are ready for a new vision to get our economy moving again. Tom Wolf will restore Governor Corbett's drastic cuts to our schools and invest in our future workforce to build a stronger middle class," said Wolf spokesman Jeffrey Sheridan.

Wolf has traveled across the state and met with workers, business owners and families who are ready for a fresh start, he said, referring to Wolf's campaign slogan.

The Wolf campaign offered no further comment on the Franklin & Marshall poll.

The next Franklin & Marshall poll will be released at the end of September, Madonna said.

-Reach Candy Woodall at