It seems David and Charles Koch, the billionaire brothers known for funding conservative and libertarian causes, have their fingerprints on the union showdown in Wisconsin. The New York Times reported on Monday that advocates from Americans for Prosperity are on the ground in Wisconsin to voice support for Republican Governor Scott Walker's budget, which is widely viewed as a union-busting measure. Americans for Prosperity receives funding from the Koch brothers, and their conglomerate Koch Industries was a major contributor to Walker's election campaign.

The battle in Wisconsin was already a story that inspired heightened emotions, but the involvement of the Koch brothers, one of the left's favorite bugbears, has brought out a new level of vitriol among liberal commentators. "The Koch brothers are clearly not [affected] by the decline of the middle class," sneers Chris Ryan at AMERICAblog, "so of course they can't relate to the financial disruptions of recent years." Gawker's Max Read riffs on Americans for Prosperity president Tim Phillips's call to "bring fiscal sanity back to this great nation." Says Read: "Why not bring back child labor and the seven day workweek, while we're at it? There's nothing fiscally sane about leaving healthy 12-year-olds unexploited."

Meanwhile, Andrew Sullivan at The Atlantic takes a more measured stance. "It's not the cutting of public sector benefits that concerns me," he writes. "I think the budget situation demands such cuts, and Walker deserves credit for saying so and following through." But combing through Walker's bill, Sullivan finds measures that don't square with the governor's stated agenda of fiscal conservatism: a "combination of no bid sales to corporations, exemptions for public sector unions like cops and firefighters who backed his election, and simultaneous tax cuts for the successful." Given the Koch connection, Sullivan writes, "the more I read, the shadier and more ideological Walker seems."

Yet Slate's David Weigel, reporting from Wisconsin, seems less than impressed over the Koch to-do. "Anger at the Kochs comes up in interviews before I've even asked about them," Weigel writes from Madison today. "Protesters call Gov. Scott Walker a puppet of the Kochs, and some of them say his budget reform bill will result in a no-bid contract win for the brothers. There's a lot to learn here, but the most basic lesson is: A lot of people in Madison read The New Yorker." (He's talking about this.)