CHICAGO The billionaire Koch brothers -- whose deep pockets and small-government philosophy have made them conservative powerhouses -- are playing an influential role in the drive to strip public employee unions of their rights to bargain in several U.S. states.
Charles and David Koch, who both rank 24th on the Forbes list of the world's richest people with $17.5 billion each, are behind campaign donations of tens of thousands, if not millions, of dollars to Republicans leading the anti-union effort.
"They're the poster boys for the incredible out-sized influence that corporate America has on our government right now," said Mary Boyle of the left-leaning group Common Cause.
In Wisconsin, state records show new Republican Governor Scott Walker's campaign received $43,000 last year from the political action committee of Koch Industries Inc, the energy and consumer products giant co-owned by the brothers.
The low-profile brothers also gave $1 million to the Republican Governors Association, which spent $3.4 million attacking Walker's Democratic opponent. Charles Koch and his wife each gave the limit of $11,000 to Republican Governor John Kasich's campaign in Ohio, which is also weighing curbs on union power.
The group Americans for Prosperity, founded by David Koch and aligned with the Tea Party movement, has launched a $342,000 advertising campaign in support of Walker's effort to end collective bargaining for most state workers.
Democrats and unionized public employees say Walker's plan is an attempt to bust unions and choke off funding to organized labor, a traditional cornerstone of financial donations and grassroots support for the Democratic Party.
The political stand-off has drawn tens of thousands of pro-union protesters, making Wisconsin ground zero in a national struggle over union power and putting a new focus on the Koch brothers.
Their role was highlighted this week when Walker took a call from a New York blogger impersonating David Koch. Thinking he was talking to Koch, Walker was caught on tape discussing his tactics to lure runaway Democratic senators back to the state and joking about using a baseball bat on opponents.
"He obviously feels a big debt of gratitude," Boyle said.
Republican-led legislatures and governors in several states faced with budget deficits have introduced plans similar to Walker's to undermine public sector unions, arguing years of one-sided negotiations have resulted in unsustainable wage, pension and benefit promises.
Among the basic tenets of libertarianism -- smaller government, less regulation, and lower taxes -- is anti-unionism, and the Koch brothers have spent hundreds of millions of dollars to buttress the movement since the 1960s.
But the timing for the union squeeze may have more to do with the emergence over the past two years of the populist Tea Party, which lifted like-minded candidates into office in 2010 and provided foot soldiers for the libertarian movement.
"This is all a wave of political belief that the Kochs unquestionably have funded in various ways for years and years and years," said Brian Doherty, editor of Reason Magazine, published by one of several think tanks funded by Koch money.
"Calling that manipulating, (saying they are) calling the shots, seems a silly, conspiratorial mind-set," he said.
Walker and Kasich voice elements of the libertarian view, looking to gain from the money and votes it attracts.
Union supporters argue Walker and other Republicans are doing the Kochs' bidding, suspicious the billionaires want to promote their business interests and curb government regulation.
Greenpeace has ranked Koch Industries among the top 10 U.S. polluters, and Koch-funded think tanks produce research papers arguing against climate change and environmental regulation.
Messages left with Koch Industries were unanswered. The privately held conglomerate generates an estimated $100 billion in annual revenues from oil refining, energy pipelines, ranching and its Georgia-Pacific packaging company's products like Quilted Northern toilet paper and Dixie cups.
Koch campaign donations are difficult to track, said a spokeswoman for Followthemoney.org, a Montana-based group that compiles state campaign donations. The group said the Kochs and related entities gave at least $539,339 to state races in 2010, with Wisconsin Republicans receiving the third-most after counterparts in Texas and Kansas.
Donors to state races are constrained by some states' restrictions on amounts and sources of funding. In Wisconsin, corporations and unions cannot give directly to candidates, but limits can be skirted by giving to state or national parties.
Critics warn last year's Supreme Court ruling allowing unlimited corporate and union spending in federal campaigns will expand the influence of the super-rich like the Kochs.
"This is part of the concerted attack on the middle class and working families of this country by the very wealthiest people in America, the Koch brothers and many others," said Senator Bernie Sanders, an independent from Vermont.
(Additional reporting by Kim Dixon in Washington)