"If they didn't have so much money, they wouldn't be able to do something with so little chance of success," said Democratic strategist Tad Devine.
Another sign that Ohio looms large for the Romney campaign: a guest-filled rally in suburban Cincinnati on Friday to kick off the campaign's final four days. Set to join the GOP ticket are golf legend Jack Nicklaus, former Secretary of State Condoleezza Rice, Texas Gov. Rick Perry and former New York City Mayor Rudy Giuliani.
Meanwhile, Democratic groups bitterly complained about a TV ad the Romney camp is running in the Toledo and Youngstown areas of Ohio. The ad suggests that Jeep will move its Toledo car-making facility to China, a claim Jeep executives deny.
Democrats called the ad a brazen lie and a sign of desperation. Even some Republicans worried that Romney has gone too far in a state where voters follow the auto industry closely.
Associated Press writer Thomas Beaumont in Des Moines, Iowa, and Brendan Farrington in Tallahassee, Fla., contributed to this report.