In case there are any Michigan voters who haven't heard, President Obama had this message on Tuesday morning as the state's primary got underway: three years ago, he helped save the auto industry with a controversial bailout. In a rousing speech to a United Auto Workers conference in Washington, conveniently timed as voters were headed to the polls in Michigan, Mr. Obama, in full campaign mode and resembling his 2008 self, reminded the labor organization's conference of a few things. "Just a few years ago, nearly one in five autoworkers were handed a pink slip," Mr. Obama said. And as the financial crisis hit with its full fury, America faced a hard and once unimaginable reality: two of the Big Three - G.M. and Chrysler - were on the brink of failure. And then, he got to the punch-line that he has been perfecting ever since the Republican campaign road-show headed to Michigan, where Mitt Romney has been trying to live down an Op-Ed piece he wrote in The New York Times in 2008 headlined "Let Detroit Go Bankrupt." Mr. Obama has been gleefully bringing that up at just about every public event. In his speech Tuesday, before a raucous crowd of the Democratic Party's labor base, gave him the ultimate platform. "Some politicians," Mr. Obama said, "even said we should "let Detroit go bankrupt!"" The crowd booed. Mr. Obama paused, dramatically. "You remember that?" he said. More boos. Another pause, then Mr. Obama started grinning, clearly enjoying himself. Think about what that choice would have meant for this country, if we had turned our backs on you, if America had thrown in the towel. G.M. and Chrysler wouldn't exist today. Mr. Obama, when he chooses to and as he did consistently in 2008 during his run for president, can turn up the oratory. The crowd of autoworkers and labor leaders were eating up every word - and their energy appeared to further amp up Mr. Obama. The president fed them one line after another, and several times detoured from his prepared remarks, like when he gave an endorsement for the new Chevy Volt that included a promise to buy one - in five years time, of course. "I got to sit in a Chevy Volt, even though Secret Service wouldn't let me drive it," Mr. Obama said, to cheers. I enjoyed sitting in it. And four or five years from now when I'm not president no more and I can drive myself, I'm gonna buy one. From the crowd came the chant every president likes to hear: "Four more years! Four more years! Mr. Obama broke into another beaming smile. It was with that smile still stretched across his face that he - again - went after Mr. Romney, although never mentioning him by name. "It's been fun watching these folks trying to completely rewrite history now that you're back on your feet," he told the autoworkers. He went into a long riff about the hard labors of union workers, and sought to turn Republican rhetoric about American values against the party. "Let me tell you, I keep hearing people talk about values all the time," Mr. Obama said, his voice rising. Hard work, that's a value. Mr. Obama even channeled Senator Edward M. Kennedy, the Massachusetts Democrat who died in 2009. "He used to say, "What is it about working men and women they find so offensive?"" Mr. Obama's campaign advisers had been enjoying Rick Santorum's rise in the polls in Michigan, and say that even as Mr. Romney has surged back in that state - the state he grew up in - they have gleaned important tips for the general election. At the top of that list, they say, will be looking for more ways to beat up Mr. Romney for writing that Op-Ed in 2008. Not surprisingly, Republicans were quick to respond Tuesday. "President Obama is known for putting his re-election over keeping his promises to the American people," said Kirsten Kukowski, a spokeswoman with the Republican National Committee. Obama's speech to U.A.W. today is no different. This is an insider deal for his union cronies who got billions in bailout money and are now backing Obama's re-election campaign.