Over at the Politico, Mike Allen reports on the early buzz among party insiders:

Democratic officials with access to exit polls say Sen. Obama looks like he’s headed for a huge win in today’s Wisconsin primary... The party officials said that if the trends reflect in the interviews with hundreds of Badger State voters, the news out of the primary will be: Obama encroached deeply into three of Clinton’s core groups of voters — women, those with no college degree and those with lower incomes — while giving up none of his own.

Based on my first look at the polling, Allen's analysis is spot-on. At this early stage--unweighted exit polling is an early glimpse, not the final word--Obama has neutralized Clinton's sustained advantages among women (51-49 Obama), families with income under $50,000 (again, Obama 51, Clinton 49) and union households (Clinton 50, Obama 49). Couple that with a two-to-one Obama edge among Independents (63-34), who made up more than a quarter of the electorate, and it's basically impossible for Clinton to emerge tonight with a "W."

Team Obama is certainly feeling confident. "Wisconsin is almost the kind of state Hillary Rodham Clinton would have invented to win a Democratic presidential primary, brimming with whites and working class voters who usually support her," spokesman Bill Burton wrote to reporters at 6:14 p.m. "A poor performance there Tuesday would raise big questions about her candidacy."

Not the sort of spin you send out when you're expecting to lose--to put it mildly.

If the exit polls are right and Obama did, in fact, cut into Clinton's core constituencies, it doesn't bode well for Clinton's chances in Ohio, where she's counting on women and working-class voters to carry her to victory. The pundits basically predicted a loss; they didn't predict that Obama would shatter the demographic pattern that's held steady since the start of primary season. Except headlines to that effect tomorrow--and a lot of teeth-gnashing and garment-rending at HRC headquarters in Arlington.