The latest Public Policy Polling survey of Ohio illustrates my point this morning about the Obama campaign's effort to keep Romney from consolidating disaffected white voters. Obama still leads Romney in the Buckeye State, 47 percent to 44 percent, but that lead has declined from 50 percent and 49 percent in previous polls.

This decline has everything to do with white voters. Romney has opened up a 7 point lead among white voters, 49 percent to 42 percent. What's more, he's lost support from white Democrats. As PPP notes, he went from an 89–6 lead in early May, to 78–16 in June. In addition, Obama has a 9 percent approval rating among undecided voters-who, in Ohio, are disproportionately white. Obama's saving grace is Romney's unpopularity; his favorability is at 9 percent, and 61 percent say they hold a negative opinion of him.

If Romney were to consolidate disaffected white Democrats, he would have a sizable lead over Obama. At the moment, however, he can't, and the Bain Capital attacks are meant to keep that from ever happening. Of course, this all depends on an economy that's no worse than the status quo; if the situation continues to decline, then there's not much Obama can do to hold Romney at bay.