But all three are too close to call and both Romney and Obama had final weekend campaign appearances in them, underscoring their fluidity. Romney has gained ground in North Carolina, which now is tipping his way. Obama's team has all but acknowledged that it's the weakest for the Democrat of the competitive states, and the president himself isn't visiting the state in the final stretch.
But the key for both campaigns is the Midwest, specifically Ohio. It offers 18 electoral votes and figures prominently in each strategy. That urgency was evident by the multiple visits to the state by each candidate in the final days.
Obama has enough of an edge in the electoral race that he could win the White House without carrying Ohio. But it's hard to see how Romney does so.
That assessment, and Obama's slight but stubbornly persistent edge in the state, could explain why Romney made a late-game play for Democratic-leaning Pennsylvania's 20 electoral votes. He began advertising heavily in the state last week and put a stop in Philadelphia on his Sunday schedule even though the state has voted for a Democratic presidential nominee in every election since 1988.
Democrats projected confidence about holding Pennsylvania, although Obama responded with his own ads in the state and was sending former President Bill Clinton to campaign for him there on Monday.
Not that Romney is writing off Ohio. No Republican has won the White House without winning the state, and, without it, Romney would need a near sweep of the other battleground states.
"Ohio, you're probably going to decide the next president of the United States," Romney said Friday at a plant near Columbus.
Refusing to cede ground in Ohio, Obama's campaign is flooding the state with four visits in as many days to every major media market by the president, first lady Michelle Obama, Vice President Joe Biden and Clinton. Obama planned to finish campaigning in Ohio on Monday at a Columbus rally with rocker Bruce Springsteen.