Mitt Romney has gone on the offensive against one of Michigan's biggest employers, the automotive industry, lambasting the bailouts to General Motors Co. and Chrysler Group LLC from President Barack Obama and proclaiming himself a son of Detroit.

Romney, who was born in the Motor City, published an op-ed in The Detroit News on Tuesday, repeating his attacks on the auto industry bailout and prompting a slew of criticism by everyone from the United Auto Workers union to Steven Rattner, the former car czar and chairman of Obama's auto task force. Romney's statements come as his poll numbers falter in his home state and nationally, with some even showing he trails former Sen. Rick Santorum.

Instead of the free market doing what it does best, we got a major taste of crony capitalism, Romney wrote in the op-ed of the bailouts.

Romney, a Michigan native and the son of a former Michigan governor and auto executive, even went after the UAW, saying the union was, in essence, rewarded for campaign contributions to Obama in 2008.

A labor union that had contributed millions to Democrats and his election campaign was granted an ownership share of Chrysler and a major stake in GM, two flagships of the industry, Romney wrote. The U.S. Department of Treasury - American taxpayers - was asked to become a majority stockholder of GM. And a politically connected and ethically challenged Obama-campaign contributor, the financier Steven Rattner, was asked to preside over all this as auto czar.

For his part, Rattner did not take kindly to the attacks. Rattner's task force helped broker the deals that sprang the government-managed bankruptcies of GM and Chrysler. Both President George W. Bush and Obama signed off on separate bailout packages in 2008 and 2009 that totaled about $85 million.

Chrysler repaid its loans in full last May, but the government is still expected to lose money on the bailouts because of its remaining stock in GM.

Rattner said that under Romney's preferred method of a traditional bankruptcy process, GM and Chrysler would have been forced to liquidate. He said credit markets were too tight for private financing to fund the companies' bankruptcies.

Rattner, in an interview with the Detroit Free Press, said Romney's stance is ridiculous and a complete denial of the facts.

He's trying to sharpen his conservative chops, Rattner told the paper. He's afraid of being perceived as a moderate.

Meanwhile, UAW president Bob King also fired back at Romney, saying he was trying to rewrite history in an attempt for political gain.

King said the auto industry's uptick, flush with new jobs, increased market share and sales and even the occurrence of the dazzling North American International Auto Show in Detroit last month would all not have happened if Romney's position had been enacted in policy.

When we were at our darkest hour, Mitt Romney turned his back on the industry, their workers and the people of Michigan and in other places where Americans depend on the auto industry, King said in a statement. He likes to say he is from Michigan, but no Michigander would advocate the bankruptcy of Detroit, talk down about auto workers and see the recovery of its economy as politically damaging to their campaign.

Other Democratic lawmakers, including former Michigan Gov. Jennifer Granholm and U.S. Reps. Gary Peters, John Dingell and Sander Levin, also blasted Romney.

Both GM and Chrysler did not respond to requests for comment.

The recovery of the auto industry has begun to form as a potential discussion point of the 2012 presidential election. Obama has already taken subtle jabs at Romney for his stance, saying there were some people who would have let the industry die. And campaign strategists suggested Obama will employ the auto industry's successes heavily if matched up with Romney in the general election.

When you look at all these cars, it is a testimony to the outstanding work that's been done by workers, American workers, American designers. The U.S. auto industry is back, Obama said at the auto show, according to a pool report.

The fact that GM is back to No. 1 I think shows the kind of turnaround that's possible when it comes to American manufacturing. It's good to remember the fact that there were some folks who were willing to let this industry die.

Bush has also defended the bailouts in a recent speech to the National Dealers Association convention in Las Vegas, saying he would do it again in the face of a potential depression.