YPSILANTI, Mich. — Mitt Romney and John McCain argued about their concern for the auto industry, while Mike Huckabee spotlighted his opposition to abortion, as the Republican presidential contenders campaigned Saturday before Michigan's potentially make-or-break primary.

Romney, seeking a rebound in Tuesday's primary after losing to Huckabee in the Iowa caucuses and McCain in the New Hampshire primary, made an impromptu stop at a General Motors plant near here after 200 layoffs were announced last week.

He pledged to make restoring the domestic auto industry — once the linchpin of Michigan's economy — a top priority if elected president.

"In some respects, Michigan is like the canary in the mine shaft: What Michigan is experiencing, the whole nation will experience unless we fix what's happening in Michigan and learn lessons here we can apply across the nation," he said in Traverse City amid a fly-around of the state.

Romney's criticism of Washington was a none-too-subtle shot at McCain, an Arizona U.S. senator who has said that some of Michigan's lost jobs are gone forever. A Detroit News poll being released today showed the race a statistical dead heat, with McCain at 27 percent and Romney at 26 percent. Huckabee was third with 19 percent.

McCain defended his comment during a raucous rally before 400 supporters in Warren.

"I had to give some straight talk," McCain said. "Jobs are leaving the state of Michigan. They have left and will not come back, but we're going to create jobs, we're going to create a new economy. This is the smartest technological place in America. We have the smartest people here. We can do it. We can create jobs here."

Later, aboard his campaign bus, McCain continued his criticism of Romney.

"Governor Romney says he supports the industry yet when he was running for the governor of another state he wanted to raise the tax on SUVs," McCain said.

Aides distributed campaign literature from Romney's 2002 race for governor in Massachusetts in which Romney proposed a 10-year sales tax moratorium on hybrid vehicles, as well as

reworking the vehicle excise tax to encourage the purchase of fuel-efficient cars.

McCain also mentioned a Detroit News headline Saturday: "Experts Back Up McCain's Jobs Claim."

Romney, sitting later in the home of an unemployed woman in Marshall, responded by criticizing McCain for supporting an increase in fuel-efficiency standards, something Michigan automakers have resisted.

"I was the governor of Massachusetts, and Massachusetts is not the state that is propelling the Michigan economy," he said. "Senator McCain was a U.S. senator, who has responsibility for the well-being of the entire country.... Senator McCain has watched as Michigan has suffered."

Economics were a focal point because Michigan's unemployment rate, at 7.4 percent in November, is a full percentage point higher than any other state. It also is about 50 percent higher than the national average.

Bureau of Labor Statistics figures show the state shed more than 76,000 jobs in the 12 months ending in November, a period in which the national economy added 1.5 million jobs.

Huckabee's alternate focus on social issues highlighted his effort to reinvigorate the coalition of religious voters that propelled him to victory in Iowa.

The former Southern Baptist minister emphasized his opposition to abortion as he urged about 100 pastors in Grand Rapids to support him and use their address books and e-mail lists to mobilize others.

"I don't presume that you will support me because of a common faith," Huckabee told them. "I know that I have to earn that. But I also recognize this is a unique opportunity. For a long time, those of us who are people of faith have been asked to support a candidate who would talk to us. But rarely has there been one who comes from us."

He added, "Life is in the balance."

While only 30 delegates were up for grabs in Michigan Tuesday, the candidate activity highlighted the state's importance in the battle for momentum.

McCain is hoping to build on his New Hampshire victory. Huckabee, the former governor of Arkansas, is trying to recapture energy heading into next week's South Carolina primary.

Romney is seeking a first-place finish after his earlier second-place finishes. Michigan is especially important: Romney grew up here and his father, George, was a three-term governor in the 1960s.

Former New York Mayor Rudy Giuliani, who was campaigning in Florida Saturday, has ceded Michigan to the others.

Contributing: Liz Sidoti and Libby Quaid