A new poll of three key swing states has some good news for presumptive Republican presidential nominee Mitt Romney: He has erased President Obama's lead in Ohio and Florida, leaving the two candidates statistically tied. In Quinnipiac University's March swing state poll, Obama was beating Romney by 7 percentage points in Florida and 6 in Ohio; now Romney's leading Obama by 1 point in the must-win Sunshine State, and Obama's Ohio lead has narrowed to just 2 points. Things look better for Obama in the third state, Pennsylvania, where he's 8 points ahead, but as Quinnipiac notes, "No one has won the White House since 1960 without carrying at least two" of these three states. What's behind Romney's boosted poll numbers? 

1. It's finally a two-man race
"What happened?" asks Chris Cillizza at The Washington Post. "In short, the primary ended" and Republicans are starting to rally around their nominee. For the first time this election season, "Romney is no longer being attacked by his fellow Republicans," says Quinnipiac's Peter Brown. And because Romney's just starting to mend bridges from the brutal primary season — while Obama went uncontested — the advantage should still go to Obama in polling, says Ed Morrissey at Hot Air. But the fact that the president can't get to 50 percent in Florida, Ohio, or Pennsylvania "has to be worrying Team Obama."

2. It's (still) the economy
Romney's rise in Florida and Ohio is primarily "fueled by voters' perceptions of the economy," says Steven Shepard at National Journal. In both states, respondents said they think the former Massachusetts governor would do a better job with the economy, while Pennsylvania voters are split. Why is that a big deal? At least 67 percent of respondents in all three states say we're still in a recession, though at least 51 percent think the economy is starting to recover. That makes the next round of jobs numbers "critical to the campaign," says Linda Feldmann at The Christian Science Monitor. "Now is when voter impressions of the economy begin to set in."

3. It's women
In Florida, "much of Obama's advantage among women has been erased," and he and Romney are running neck-and-neck. The bright spot for Obama is Pennsylvania, and that's largely because he's "blowing Romney out of the water among women," beating him by 17 points, says National Journal's Shepard. Obama has a 13-point lead among women in Ohio, but Romney balances that out with a 10-point lead among men. "Obviously there are six months to go, but this is a good indication of the tightness of the race," says Quinnipiac's Brown.