Mark Halperin's 5 Things to Watch on Election Day

2. Pay Attention at 7:30 PM ET

Three key states — Virginia, Indiana and Ohio — have polls that close by 7:30 p.m. ET. If Obama wins just one of these, McCain's chances go from slim to next-to-none. If Obama wins two or three, look for early talk of a Democratic rout. But if McCain takes all three, to channel Dan Rather, the night will be as long as the first-place winner in a Beyoncé–Jessica Simpson hair-extension contest.

Read dispatches from the election frontlines.

Watch TIME's video, "In Indiana, Red-County Blues."