In an interview with Rolling Stone, President Obama called Mitt Romney a “bull­s----er.” But here in Ohio, it is Obama who is peddling the B.S. when it comes to Romney and automobile-company bankruptcy. The question is: Will Obama’s bankruptcy B.S. win him the Buckeye State — and with it a second term in the White House?

The president clearly is betting on it. An Obama campaign ad running here declares that Romney wanted the auto industry to “fail,” and an auto worker says, “Mitt Romney would have just let us go under, just let them go bankrupt.”

Three years ago, Obama was singing a different tune when it came to bankruptcy. “I know that when people even hear the word ‘bankruptcy,’ it can be a bit unsettling, so let me explain what I mean,” Obama told worried auto workers in 2009, when he announced that hemight take GM and Chrysler bankrupt — as indeed happened weeks later. Bankruptcy, the president said, is simply a “tool that we can use” to “make it easier for General Motors and Chrysler to quickly clear away old debts that are weighing them down so they can get back on their feet and onto a path to success.” It is not, Obama insisted, “a process where a company is simply broken up, sold off, and no longer exists.”

Now Obama using the “B” word to suggest that is exactly what Romney wanted to do.

So how does Obama attack Romney for wanting to take GM and Chrysler bankrupt when he actually took them bankrupt? Romney, Obama claims, would not have provided “government assistance to the U.S. auto companies, even if they went through bankruptcy,” adding that “we would have lost a million jobs.” This is false. Romney wanted the federal government to guarantee private-sector loans, while Obama wanted the federal government to provide the loans directly. No matter, Obama continues to peddle the falsehood that Romney would have let GM and Chrysler die, declaring at a Cleveland rally last week, “If Mitt Romney had been president when the auto industry was on the verge of collapse, we might not have an American auto industry today.”

While the facts are on Romney’s side, the messaging is not. The Romney campaign allowed Obama to dominate the airwaves for months and to hammer Romney with bankruptcy attacks without responding — allowing the impression to harden that Romney opposed federal help for the auto industry.

Sen. Rob Portman (R-Ohio) has been a lonely voice in countering the Obama bankruptcy assault. He wrote an op-ed, published Friday in Cleveland’s Plain Dealer newspaper, in which he declared, “The question was never whether to let Detroit go under, but how best to save it.” And at a rally in Defiance, Ohio, last week, while Romney didn’t mention the bankruptcy issue, Portman took the argument head-on: “Mitt Romney did propose government help. . . . And folks, all the independent fact-checkers who have looked at this agree: President Obama . . . [is] not telling the truth.”

Portman knows how to win in Ohio. He beat a sitting lieutenant governor by 18 points just two years ago and is widely credited with helping Romney to achieve his narrow Ohio primary victory in March. And it seems Team Romney is belatedly starting to follow his lead. Over the weekend, the Romney campaign finally released a new ad that goes on the offensive on the auto bankruptcy issue. “Obama took GM and Chrysler into bankruptcy and sold Chrysler to Italians who are going to build Jeeps in China,” the narrator says as the screen shows two American cars getting crushed at a scrap yard. “Mitt Romney has a plan to help the auto industry. He is supported by Lee Iacocca and The Detroit News.”

The campaign is also beginning to highlight the fact that Obama’s plan was, in Portman’s words, a “political bankruptcy” that put the government in charge of “picking winners and losers.” GM plants in Mansfield, Columbus and Parma were shut down, and more than 100 local dealerships in Ohio were among the losers in Obama’s plan. This weekend, Paul Ryan held a round-table with retirees from auto-parts maker Delphi who were cut out of the government deal and saw their hard-earned pensions shrink by up to 70 percent.

A Cincinnati Enquirer/Ohio Newspapers poll last weekend shows the race now tied at 49 percent apiece— which means Ohio, and ultimately the presidency, could hinge on who wins the fight over the auto bailout. Will the late-breaking Romney counterassault be enough to turn the tide, or is it too little too late? We’ll know the answer in eight days.

Marc A. Thiessen, a fellow with the American Enterprise Institute, writes a weekly online column for The Post.