This post has been updated.

As Michigan voters headed to the polls for the state’s Republican primary Tuesday, President Obama hailed his administration’s bailout of the Detroit auto industry in Washington, saying that he had “placed my bet on the American workers” when his GOP rivals would have let the companies go bankrupt.

Obama used an appearance before a boisterous crowd of 1,600 at the United Auto Workers Conference to hammer home a contrast between him and the Republican presidential candidates, particularly former Massachusetts governor Mitt Romney.

Since launching his national jobs tour in Detroit on Labor Day last fall, Obama touted the decision three years ago to grant emergency federal loans to General Motors and Chrysler. He again reminded his audience that his Republican rivals opposed the government assistance.

“I placed my bet on American workers,” Obama told the auto workers, who greeted him with cheers of “four more years.”

“And I’d make that same bet again any day of the week. And now, three years later that bet is paying off,” he said. “Not just paying off for you. Paying off for America. Three years later, the American auto industry is back.”

The boasting comes as sales for the big three U.S. automakers — General Motors, Ford and Chrysler — could surpass 14 million this year, well above last year’s 12.8 million, the Associated Press reported Tuesday. GM posted a record $7.6 billion profit in 2011.

Though he didn’t mention Romney by name, Obama aimed squarely at the GOP contender, who penned a New York Times op-ed column in 2008 titled “Let Detroit Go Bankrupt.”

In the op-ed, Romney argued for a managed bankruptcy of the auto companies. The former specialist in private-sector corporate takeovers reaffirmed his position in a Detroit News column two weeks ago. He referred to Obama’s bailout as “crony capitalism on a grand scale.”

“The president tells us that without his intervention things in Detroit would be worse,” Romney wrote. “I believe that without his intervention things there would be better.”

Still, Romney has been hurt by his stance while locked in a tight Michigan primary race with former Pennsylvania senator Rick Santorum. Last week, auto union workers protested Romney’s views outside Ford Field, where Romney was addressed supporters in the football stadium.

On Tuesday, United Auto Workers President Bob King introduced Obama by saying: “When we had Republicans attacking us, our next speaker stood behind us and saved our job and saved our industry.”

Obama played to the crowd, referring obliquely to Romney's criticism of the federal bailout as a payback for unions, saying: “Really? Even by the standards of this town, that’s a load of you-know-what.”

“Who knows,” the president said, “maybe the naysayers would finally come around and say that standing by American workers was the right thing to do.”

Buoyed by the support of the workers, Obama noted that during a tour of a Detroit factory he had sat in a Chevy Volt.

“And five years from now, when I’m not president any more, I’ll buy one and drive it myself,” he said, as the audience cheered.