The first post-poll-closing exit poll in Ohio gives Barack Obama a narrow lead over Mitt Romney, wholly in line with the final polls. The internals indicate one of two things: Either black turnout has increased and made this thing more competitive for Obama, or we're going to get a second round that wipes out the lead.
Here's what I mean. In 2008, Obama won 46 percent of Ohio whites. He's now winning 42 percent. That's right at the bottom of what he should be able to get to eke something out. But this poll has the black vote surging as a proportion of turnout, from 11% to 15%. If one of these numbers skews back toward Romney -- like, the black vote falls to 12% -- we're at a tie. But if it doesn't, Obama has buillt a new coalition that wins him the state, and Pennsylvania.