President Obama and Mitt Romney are neck-and-neck in national polls, but in the Electoral College, things are looking pretty good for Obama, thanks to his small but persistent leads in polls of Ohio and other key swing states. In The Washington Post's round-up of election prognostications, only two of the 13 crystal ball gazers picked Romney to win on Tuesday. Still, Obama is by no means a shoo-in, and a few thousand votes in any number of states could end his presidency. Here's what Obama needs to do to get the magic 270 electoral votes:

According to the AP, the president is "all but assured of 249 votes" — counting Iowa, Nevada, and Pennsylvania, which are all states that Team Romney considers in play — while Romney can lay claim to 206 electoral votes, including North Carolina (which Obama won in 2008). That leaves 83 electoral votes on the table — in Ohio, Florida, Virginia, Colorado, New Hampshire, and Wisconsin — and Obama only has to pocket 21 of them to win. (You can play around with different scenarios at CNN's electoral map.)

Obama has 431 distinct paths to re-election, versus 76 for Romney (and five to a tie), according to The New York Times, which adds North Carolina, Iowa, and Nevada to the AP's list of in-play states. That means Obama could win just by taking Florida (29 votes), or Ohio (18) and any other state. He could also win with Wisconsin (10) and Virginia (13), or either of those states plus Colorado (9) and New Hampshire (3). In most of these states, the polls are pretty tight. "It's really a game of inches," Ipsos pollster Julia Clark tells Reuters. "It's extremely close, but things look pretty optimistic for Obama, I would say, if you do the electoral math." 

If the networks call Virginia for Obama after the polls close there at 7 pm (ET), that's a clear sign the president is cruising to re-election, says Ruby Cramer at BuzzFeed. Even if Obama loses Virginia, but takes North Carolina or Ohio (7:30 ET), or Florida (8 ET), you can start pouring the victory champagne (or drown-your-sorrows bourbon). But if Obama doesn't take any of those states, watch for Pennsylvania (8 pm). If he loses there, he's lost the White House.

Obama shouldn't count his chickens before they hatch, says Romney political director Rich Beeson. In states with early voting, compare this year's returns with Obama's last victory and you'll see "there is a general underperforming in places where President Obama needs to do well and there's an over-performing in places where Governor Romney does well." Team Romney also argues that it has the organic enthusiasm in the race, and that it is expanding the map of contested states, setting up upsets in places like Pennsylvania, Wisconsin, and Michigan. That's nonsense, responds Obama chief strategist David Axelrod. "I'm not suggesting we're going to win by the same margin we won in 2008... but we're doing plenty well — and well enough to win this race."

Sources: AP, BuzzFeed, CNN, Fox News, New York Times, Reuters, Washington Post

Read about Romney's paths to electoral victory here.