DETROIT Republican presidential candidates Mitt Romney and John McCain traded charges over the economy and abortion on Monday, in what has become a bitter personal duel on the eve of the important Michigan primary.
Democratic rivals Barack Obama and Hillary Clinton, meanwhile, tried to put their recent clash over race behind them before Saturday's nominating contest in Nevada, where a new poll showed a tight battle.
One day before the Republican contest in Michigan, where Romney and McCain are neck-and-neck in new polls, the focus was on the state's slumping economy as Romney promised to "roll up my sleeves" and turn around the auto industry.
Romney, a former Massachusetts governor, is hunting for a breakthrough win in Michigan on Tuesday after second-place finishes in Iowa and New Hampshire. A third failure could effectively end his White House dreams.
Victory by McCain would cement him as Republican front-runner but he would still face challenges from former Arkansas Gov. Mike Huckabee and former New York Mayor Rudy Giuliani in upcoming contests in South Carolina and Florida.
Romney, a former venture capitalist contrasted his approach to economic problems with "Washington politicians" like McCain, a veteran U.S. senator from Arizona, whom he painted as a pessimistic insider.
"Michigan can once again lead the world's automotive industry, but it means we're going to have to change Washington," Romney, who was raised in Michigan, said in a speech to the Detroit Economic Club.
"We're going to go from politicians who say they are 'aware' of Michigan's problems to a president who will do something about them," he said.
McCain also promised to work for a turnaround in the auto industry and pledged to create new jobs. "I will herald a new day in Michigan," he said during a swing through the western part of the state.
The economy has vaulted to the top of the campaign agenda in Michigan, which has posted the highest unemployment rate among U.S. states for much of the past year partly due to an auto industry slump.
Michigan's 7.4 percent unemployment in November was 3 points higher than the national rate.
A new Reuters/C-SPAN/Zogby poll in Michigan showed McCain, who won the New Hampshire primary last week, narrowly leading Romney 27 percent to 24 percent in the state -- within the poll's margin of error of 3.3 percentage points. Huckabee, who won Iowa, was running a distant third at 15 percent.
The Republican primary in Michigan is the next fight in the state-by-state process of choosing candidates for November's election to succeed President George W. Bush.
McCain defended mailers he sent out in South Carolina, which votes on Saturday, accusing Romney of supporting state funding of abortions in Massachusetts.
Romney has said state courts required any health care plan to include the funding. McCain, who has frequently complained about Romney's "negative" attacks, said he was fighting back.
"I think that's not negative campaigning, I think it is what his record is," McCain told a Kalamazoo news conference.
The day after a dispute over race roiled the Democratic nominating fight, with Clinton accusing Obama of distorting remarks she made last week about the 1960s U.S. civil rights movement, both candidates tried to put the clash behind them.
Clinton said on Sunday Obama was deliberately distorting her remarks from last week that some interpreted as giving U.S. President Lyndon Johnson more credit than black leader Martin Luther King for advancing the landmark 1964 Civil Rights Act.
Obama, an Illinois senator who would be the first black president, called the charge "ludicrous" and said Clinton had offended some Americans. But on Monday, he praised the commitment to civil rights of Clinton and her husband, former President Bill Clinton.
"I've been a little concerned about the tenor of the campaign over the last few days," Obama told reporters in Reno, Nevada. "We share the same goals, we are all Democrats, we all believe in civil rights we all believe in equal rights."
The former first lady, speaking to a predominantly black audience of union and church members in New York, took an equally conciliatory tone. She hailed the fact the Democratic Party's top two candidates were a woman and a black man.
"Each of us, no matter who we are or where we started from, is a beneficiary of Dr. King," Clinton said. "Both Sen. Obama and I know that we are where we are today because of leaders like Dr. King and generations of men and women like all of you."
With Obama and Clinton splitting the first two contests in Iowa and New Hampshire, the outcome in Nevada could provide crucial momentum to the winner.
A new poll showed a statistical dead heat in Nevada, which holds the next Democratic nominating contest on Saturday. Obama polled 32 percent, Clinton, a New York senator, was at 30 percent and John Edwards, a former North Carolina senator, at 27 percent.
(Additional reporting by Andy Sullivan in Michigan, Adam Tanner in Nevada, Jeff Mason in New York; Writing by John Whitesides; Editing by Jackie Frank and Alan Elsner)
(For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)