Probably a combination of a marginally improved economy and the ongoing tribal warfare in the Republican party.

CNN:

President Barack Obama holds a double-digit lead over GOP presidential candidates Mitt Romney and Rick Santorum in hypothetical general election matchups, according to a new poll.

And a CNN/ORC International survey released Wednesday also indicates that the president's approval rating has inched over the 50% mark in CNN surveys for the first time since last May, when the polls were still registering the after effects of the death of Osama bin Laden. The number of Americans who say the economy's in good shape has jumped 13 points since January, though the survey shows a majority still think it is in poor shape.

If the general election were held today instead of in early November, 54% of registered voters say they would back Obama, with 43% supporting former Massachusetts Gov. Mitt Romney, the front-runner in the GOP nomination battle. That's up from a five-point 51%-46% advantage the president held over Romney in February.

And Obama would have a 55%-42% lead over Santorum, the former senator from Pennsylvania who's Romney's main rival right now for the nomination. The president led Santorum by a seven-point 52%-45% margin last month.

"President Obama currently wins majority support among groups that have been problematic for him in the past, including men, older voters, and suburbanites," says CNN Poling Director Keating Holland. "He has a solid lead among independents as well."

The president's approval rating has been yo-yoing above and below 50% for several months, but this is one of the first surveys that shows Obama with a double digit lead over Romney.

Who knows what it will be next month? While this kind of unpredictability gives the GOP hope, what has been a constant is the president's ability to raise massive amounts of cash that threatens to overwhelm Republicans on the ground in November.

Unless a way can be found to offset the president's ground game, states like Ohio, Florida, and Pennsylvania will be out of play and other states like Virginia and North Carolina will be even more difficult to bring into the GOP column.