Labor unions have strongly supported Democratic Party candidates for decades. And the United Auto Workers union conference in Washington on Tuesday gave the president an enthusiastic reception that at times sounded like a political rally.

　　“The economy is getting stronger. The recovery is speeding up. Now is the time to keep our foot on the gas, not put on the brakes. And I am not going to settle for a country where just a few do really well and everybody else is struggling to get by," said Obama.

　　The president in 2009 authorized a payment of almost $25 billion to struggling U.S. automakers General Motors and Chrysler. Today, GM has regained its position as the world’s biggest car company. Chrysler is growing. And Obama is claiming at least partial credit for their success.

　　“Three years later, three years later, that bet is paying off. It is not just paying off for you. It is paying off for America. Three years later, the American auto industry is back,” said Obama.

　　Many Republicans at the time opposed the bailouts. They were concerned about the huge cost to taxpayers and the prospect of government involvement in private industry. Mitt Romney, now a leading contender for the Republican presidential nomination, wrote an opinion column in The New York Times newspaper in 2008, titled “Let Detroit Go Bankrupt.”

　　Speaking to the auto workers Tuesday, the president did not mention former Massachusetts Governor Romney by name, but he ridiculed the column.

　　“Some even said we should ‘let Detroit go bankrupt.’ You remember that. You know," said the president.

　　White House officials denied that the president’s appearance was a campaign speech.

　　Obama, however, did speak on the same day that voters in the Midwestern state of Michigan, the base of the U.S. auto industry, were voting in a Republican Party primary election.

　　While campaigning in Michigan earlier this month, Romney said the auto industry bailout was done in exchange for big campaign contributions to Obama from the United Auto Workers.

　　Meanwhile, the president announced that he has signed an executive order creating an agency to monitor trade violations by America’s trading partners. He again singled out China.

　　“We are doing it today. I am creating a Trade Enforcement Unit that will bring the full resources of the federal government to bear on investigations. And we are going to counter any unfair trading practices around the world, including by countries like China,” said Obama.

　　Obama reminded the auto workers that he had signed into law a trade agreement with South Korea, which he said will result in more American cars being sold there.