The governor's race entered an aggressive new phase Wednesday afternoon about the time Pennsylvanians came home from work or school and turned on their local TV news.

Out came a pair of campaign commercials by Democrat Dan Onorato assailing his GOP rival, Tom Corbett, as a budget-buster, a property-tax-raiser, and a fleet-car abuser, not to mention a candidate who had insulted laid-off workers.

For the record, the first negative ads of the 2010 gubernatorial race came 34 days - just under five weeks - before the Nov. 2 election.

Christopher Borick, who teaches political science at Muhlenberg College, said viewers around the state should now expect to see barrages of negative ads from both candidates.

Each has been hoarding millions of dollars for just this moment of the race. Look out for torrents of claims and counterclaims as each side splits hairs on the facts.

"I would be shocked if this wasn't the beginning of many more ads," Borick said.

The Onorato ads, running statewide, do not attack Corbett personally, but stick to Onorato's interpretation of campaign issues.

The Corbett campaign ducked questions Thursday about when it would fire back. But campaign aides have said for weeks they were locked and loaded, and ready to join the air war when it began in earnest.

Conventional political wisdom suggested that Onorato had to fire first. Trailing in polls, he must break the status quo in order to catch up.

Onorato's campaign termed both of his new ads "comparative," not negative. They seek to do double duty by introducing Onorato to voters in a positive way while trying to knock Corbett down a peg or two.

Corbett, in a statement Thursday, said Onorato was trying to "distract and mislead" with ads that include "unsubstantiated, mis-sourced attacks."

He then took a few oral pot shots at Onorato in turn.

Each side parsed its words carefully Thursday as the candidates sought to characterize the truthfulness of statements in the ads.

One of the ads says Corbett, as state attorney general since 2004, had "requested budget increases every year." That is true, but Corbett has said the requests were necessary partly to pay the increased salaries and benefits for state workers negotiated, not by him, but by Gov. Rendell, a Democrat.

The same ad says Corbett "raised property taxes 20 percent." Again, true. But most viewers would never know that the ad refers to a time, in the 1980s, when Corbett was a township commissioner in his hometown of Shaler, Pa. As attorney general, he has no authority over tax policy.

Another claim in the ad - that "Corbett's office abused taxpayer-funded cars" - was hotly disputed by the Republican candidate.

As evidence for his claim, Onorato cited a political flare-up in May between Corbett and Rendell. Corbett, then trying to win the GOP primary, had aired a TV ad saying he planned to save money as governor by cutting the state's car fleet. Rendell retorted that the car fleet in the Attorney General's Office was proportionally larger than in most state departments, and he called Corbett a hypocrite.

Corbett on Thursday shot back at Onorato, saying that the reason his office needed so many cars was that it had started a task force to fight gun crime in Philadelphia.

What was Onorato saying? Corbett asked. That he was against fighting gun crime?

"In his desperation to mislead Pennsylvania voters, Dan Onorato attacks Tom Corbett's actions as attorney general to protect and defend Pennsylvania families," said Brian Nutt, Corbett's campaign manager.

The second Onorato ad had a slightly different set of criticisms aimed at Corbett.

It accused him of supporting policies "that costs thousands of jobs." Asked to justify this claim, the Onorato campaign said Corbett had backed former President George H.W. Bush - and that Bush's policies had cost jobs.

On yet another front, the Onorato ad says "Corbett insulted Pennsylvania's workers, saying they'd rather collect unemployment than work."

This is a reference to comments Corbett made over the summer. He said he had noticed many help-wanted ads in the papers, and said he suspected that some workers would rather collect benefits than aggressively look for a job.

Pennsylvania GOP leaders said privately at the time that, right or wrong, Corbett was foolish for making such comments. Corbett said he had not meant to insult anyone.

In his ads, Onorato makes claims of having reduced the county payroll over his seven years as the Allegheny County executive in Pittsburgh.

A counterclaim from Corbett showed the fine lines of difference that can get blown out of proportion in political ads.

Corbett, in denying an Onorato claim, said that, in fact, the county payroll had jumped by 343 positions.

How could that be? Employment is either up or down. That's not a matter of opinion.

The answer appears to be that it depends on whom you count.

The Onorato team said the number of employees whose salaries are paid by the county is down - by 563 positions. It suggested that the jobs Corbett referred to must be other county jobs - paid for by state and federal grants.

Contact staff writer Tom Infield at 610-313-8205 or