The political press has declared Ohio and its 63 up-for-grabs delegates the most important GOP prize on Super Tuesday, so good news for Mitt Romney: Several polls over the weekend show him charging into a lead over Rick Santorum, or at least battling to within the margin of error. He was behind Santorum in the Buckeye State by double digits as recently as a week ago. How did Romney fight his way back in the crucial Midwestern swing state? Here, four theories:

1. Romney's benefiting from his "inevitability"
After five back-to-back wins, including a notable victory in Saturday's Washington State caucus, "Romney is close to getting his mojo back," says Josh Kraushaar in National Journal. His advisers now see his momentum sweeping him to a big win in Ohio, and the "larger and more enthusiastic" crowds greeting him lend that theory credence. Romney definitely "continues to benefit from a sense of inevitability," says Chris Cillizza in The Washington Post. In an NBC/Marist poll, 70 percent of likely Ohio voters say Romney will be the nominee, versus 13 percent for Santorum.

2. Ohioans put a premium on beating Obama
Santorum trounces Romney among Republicans who are following their heart, but "Romney wins by a large margin among those who want to pick someone who can beat Barack Obama," says Ed Morrissey in Hot Air. And the latter group is only growing as the election grows nearer. That's a big boost for Romney, says Dana Pretzer in Scared Monkeys. In the NBC/Marist Ohio poll, "likely GOP primary voters prefer electability over ideology" by a 57 percent to 36 percent margin and "momentum is obviously on the side of Romney."

3. Romney's outspending Santorum, again
"Romney's biggest edge is readily apparent every time a TV set is turned on," says Alex Roarty in National Journal. As in other close contests, Romney and his allies are pouring cash into Ohio — $3.6 million, according to the AP — with many of the ads pretty rough on Santorum. The $500,000 Santorum and his allies have spent "looks like a pop gun in comparison." Looking at the polls, says David Brody at Christian Broadcasting Service News, it's clear that Romney's "financial airwaves assault is having a tremendous effect."

4. Santorum shot himself in the foot
Santorum's "overtly social conservative message" and "incendiary rhetoric" are problematic in Ohio, where the "relatively small evangelical population doesn't have the influence it does in other, more conservative states," says National Journal's Roarty. With Romney focusing on the economy, it sure looks like "Santorum is doing everything possible to blow this last chance to prolong the inevitable," says Greg Dworkin in Daily Kos. Yes, social issues are his thing, but "if the only thing you know about the candidates is that Mitt is rich, and Santorum thinks you're damned, well, that's a helluva choice to make on Tuesday."