THIS IS no prank.

The political movement spearheaded by the increasingly in-the-news billionaire Koch brothers - libertarians who spend vast amounts fighting against unions, government regulation, global warming and other liberal causes - is stepping up its efforts here in Pennsylvania.

Last week, the president of a tea-party-linked political group heavily funded by the Koch oil-and-gas fortune - Tim Phillips of Americans for Prosperity - told reporters covering the labor unrest in Wisconsin that Pennsylvania is one of three states, along with Ohio and Indiana, where the group plans a push to curb union benefits and power.

Americans for Prosperity, or AFP - the national budget for which has soared to $40 million in the past two years with support from the Koch brothers and like-minded wealthy conservatives - sent another strong signal last week when it announced that former Reading-area lawmaker Sam Rohrer, who was backed by many tea-party groups when he ran for governor in the 2010 GOP primary, will serve as the group's state executive director.

"I personally believe - and I think AFP would underscore this - that anybody who's paid by the public, who's paid by the taxpayers, has neither the right to strike nor the right to collective bargaining," Rohrer said in a phone interview. But he also acknowledged that any specific agenda in Harrisburg for AFP or the tea-party groups that work with it would depend heavily on the details of the spending plan that new GOP Gov. Corbett will unveil early next month.

Corbett - whose campaign received a $5,000 donation from the Koch Industries Political Action Committee three weeks before he defeated Democrat Dan Onorato in last fall's election - has given no sign that he's eager to emulate Wisconsin Gov. Scott Walker's push to all but end collective bargaining by unionized state workers. But the Pennsylvania Republican has voiced support for a so-called right-to-work law here - which would allow workers at unionized companies to opt out - and indicated he might support a push to bar teachers from striking.

Such moves would likely please the reclusive Koch brothers - who were virtually unknown to most Americans a year ago but have gained notoriety for their efforts to provide a financial infrastructure to the tea-party movement that played such a critical role in boosting Republicans both in Pennsylvania and in the national elections.

Indeed, it was the lead story on the national news last week when a liberal blogger from Buffalo pretended to be billionaire David Koch in a prank call and somehow got through to Wisconsin's Walker for 20 minutes, as the fake "Koch" urged the Badger State governor to bring a baseball bat to negotiations and suggested planting "troublemakers" among the union demonstrators flooding the streets of Madison.

Walker probably didn't pick up on the prank because the Koch family has been known for hardball politics for more than a half century. Fred Koch - the family patriarch, whose innovations in crude-oil refining ultimately led his Wichita-based Koch Industries to become the largest privately held company in America - was an early backer of the ultra-right-wing, anti-Communist John Birch Society back in the late 1950s.

The family enterprise now is run by two of his sons, company chairman Charles Koch and David Koch, the executive vice president who also ran as the Libertarian Party candidate for president in 1980, when Republican Ronald Reagan was elected. Over the decades, the Koch brothers have stepped up their political visibility, heavily financing the libertarian Cato Institute and groups in opposition to global-warming theories, in addition to the Americans for Prosperity, which the brothers founded in 2004.

The Koch operation spread its political donations across Pennsylvania in 2010; for example, Koch Industries sources donated some $26,400 to the successful campaign of new GOP Sen. Pat Toomey, according to watchdog

But perhaps nowhere has its newfound clout been more on display than in the labor battle in Wisconsin, where Koch sources donated about $43,000 to Walker's coffers in last year's campaign. AFP's Phillips told the New York Times that his Koch-funded group "thought it was important" for the new conservative governor to bring on the labor showdown in Madison that has riveted the nation for the last two weeks.

In Harrisburg, the task of energizing AFP's campaign for deep cuts in government spending - with a major hit for public-sector workers - falls upon Rohrer, a nine-term lawmaker and anti-tax activist from Berks County who surrendered his seat for a doomed primary bid last year against then-attorney general Corbett. Now, the tea-party movement favorite has the job of lobbying the man who defeated him, and Rohrer acknowledged that any 2011 push by AFP would be shaped by what Corbett proposes to close an estimated $5 billion budget gap.

"I think he's going to deal with the substance - no more kicking it down the road," Rohrer said of seeking substantial givebacks from state employees. But, like most observers, he expects Corbett to at least first seek those concessions through collective bargaining, since the major state employee contracts expire at the end of June.

"I know Tom Corbett - he's a decent guy," said Democratic U.S. Rep. Bob Brady of Philadelphia, a longtime labor activist. "He doesn't want to balance the budget on the backs of the middle class."

Still, with a push from tea-party-movement lawmaker Rep. Daryl Metcalfe, legislative observers also expect more serious debate than usual from the new and more conservative state body politic about two proposals that would have been dead-on-arrival in past sessions when Democrats held much greater clout.

One of these bills slated for introduction by Metcalfe is "right-to-work" legislation, similar to laws already on the books in a number of Sun Belt states that give new hires the right to opt out of a company's employee union. Aides to Corbett said this week that the governor would sign such a bill but said they doubted that the measure would reach his desk.

The other proposal, also sponsored by Metcalfe, would undo the right of public-school teachers to strike that was granted in Pennsylvania's Act 195, on the books since 1970. Corbett said during the 2010 campaign that he is open to such a measure - backed by some school-district activists in the Philadelphia suburbs - but most experts also consider that a long shot.

Despite the long-term decline of organized labor in the United States, Pennsylvania remains a relative union stronghold, trailing only California, New York and Illinois in the number of card-carrying members. It will be a tough nut for any Koch brother - real of prankster - to crack.