Outside money has entered the Pennsylvania governor's race in a big way, with a new ad from billionaire Tom Steyer's NextGen Climate super PAC accusing Gov. Corbett (R) of giving favorable treatment to oil and gas companies while shortchanging public schools.

The ad, running statewide, demands that Corbett publicly disclose the meetings and communications he's had with oil-and-gas lobbyists and donors.

"Oil and gas companies gave Gov. Corbett $1.7 million in political contributions and he gave them a sweetheart deal on taxes that's costing Pennsylvania billions," a voiceover says in the spot. "Corbett's mismanagement has caused a huge budget deficit and his education cuts are forcing teacher layoffs and class sizes."

This is a reference to Corbett's policy decision to resist an extraction tax on natural gas production from the booming Marcellus shale formation in the state; all other states with gas and oil exploration to impose some level of production tax. Democrats have pushed the point that this has deprived Pennsylvania of revenue that could have avoided cuts to the state share of education funding earlier in Corbett's term.

Corbett faces what polls suggest is, at the moment, an uphill battle against Democrat Tom Wolf, a York businessman and former state revenue secretary.

Steyer has set himself the goal of becoming a counterbalance to the Republican-supporting Koch brothers, advocating for policies to slow the rate of change in the earth's climate.

The Republican Governors Association attacked Steyer as a hypocrite, noting that he built his fortune in part on his former ownership of stakes in coal and other so-called "dirty" energy companies.

"For years, Steyer profited big by investing in the kind of energy projects Pennsylvania relies on for good jobs and affordable energy, but now he's out to curry favor with the far left by bankrolling Tom Wolf's campaign under the guise of climate change advocacy," said RGA Communications Director Gail Gitcho. "It's clear that Tom Steyer is a hypocritical liberal billionaire with personal political ambitions."