A new television ad from Mitt Romney’s campaign shows how much the presidential election in Ohio is still turning on the battle to shape voter opinion of the Obama administration’s auto bailout. It has also revived a campaign debate over plans by Chrysler Corp.’s Jeep unit to build cars in China.

The new ad, which aired over the weekend in Ohio, challenges President Barack Obama’s effort to take credit for saving U.S. auto jobs with his government-backed rescues of General Motors Co. and Chrysler. The ad aired as a new poll for Ohio newspapers suggested that the race for Ohio’s 18 electoral votes is a dead heat.

The new Romney ad, which features nostalgic images of people enjoying rides in their cars, and then autos getting crushed at a junkyard, states that Mr. Obama “took GM and Chrysler into bankruptcy, and sold Chrysler to Italians who are going to build Jeeps in China.”

The ad draws on the fact that Chrysler and its Italian parent, Fiat S.p.A, are in talks to build a Jeep assembly plant in China to serve growing demand for Jeep models there.

The Obama campaign cried foul. In responding to the ad, it noted that last week Mr. Romney had made the more aggressive statement that Jeep was planning to move all production to China, which Chrysler says is not the case. The Obama campaign accused Mr. Romney of “trying to scare Ohioans.’’