Obama Just Won Ohio. Why That Means It's Over.

The networks won't call it for awhile. The winner won't reach 270 for another hour or two. But it just became pretty much impossible for John McCain to win the 2008 election.

Why? One word. Ohio.

In case you missed it, the networks just called it for (drum roll, please) Barack Obama.

The math is simple. With no (plausible) blue states left for McCain to pick up, his best-case scenario was matching George W. Bush's 2004 total of 286 electoral votes. Subtract the Buckeye State's 20 EVs--and New Mexico's five (it was also called around 9:30)--and he's at 261. There simply aren't enough winnable electoral votes on the table to lift McCain to 270. And we haven't even received the final results from Virginia, Iowa, Colorado, Nevada, Florida, Indiana and North Carolina--all plausible (some probable) Obama pickups.

So how did Obama do it?  By winning voters who are worried about economic conditions--a full 86 percent of the electorate--by 12 points. By outperforming Kerry's 68 percent margin among black voters by a shocking 27 points. By beating McCain among every age group under 65--after Kerry lost every age group over 30. By clobbering McCain 60-37 among voters making under $50,000 and tying him among those making over $50K; Kerry, for the record, won the first group 58-42 and lost the latter group by a massive 58-42 margin. Obama even won whites making under $50K. It was, simply put, a commanding performance--the product of campaigning in 18 different counties versus Kerry's nine, opening twice the number of field offices and dispatching three times the number of staffers. Money matters, and some combustible combination of Obama's wealth and Ohioans' worries made all the difference.

A McCain aide just told Marc Ambinder, "at this point, we need a miracle." At this point, I'm not even sure that would do it.

Fact is, miracles don't trump math. And John McCain - Ohio = President Obama. All that's left to figure out is the size of his victory.