Obama was speaking in a pre-convention campaign swing to members of the United Auto Workers Union in Toledo, a city like many in Ohio where the economy is heavily dependent on the auto industry. Obama injected that industry with huge amounts of government money in the earliest days of his administration, preventing General Motors and Chrysler Corp. from likely going out of business and laying off more than one million workers.

Romney opposed the auto bailout and accuses Obama of profligate government spending that Republicans contend has done little to lift the country out of the economic morass after the Great Recession and near meltdown of the country’s financial system, events that date to the presidency of Republican President George W. Bush.

The Republicans showed their political arguments last week during their convention that officially nominated Romney in Tampa, Florida. The theme of that gathering: Obama is a failed president.

The Democrats are fighting back and Obama said on Monday that watching the Republicans was like seeing an old television program in black and white.

Ohio is perhaps the most critical state for both candidates on Nov. 6, Election Day. It is one of seven so-called swing states that will determine the outcome of the vote. Those states do not reliably vote for the presidential candidate of one party or the other.

Since the U.S. president is not chosen by the nationwide popular vote but in state-by-state contests, the swing states have outsized influence and receive the bulk of campaign attention from the candidates.

As Obama issued a rousing call for the support of working men and women on Labor Day, the U.S. holiday the honors workers and serves as an unofficial end to the Summer holiday season, his campaign surrogates were trying to put their economic message back in positive territory.

The campaign was trying to recoup after a weekend in which key Democrats acknowledge Republican claims that Americans are not better off four years after the president swept into the White House on a message of hope and change.

From Toledo, Obama planned to travel to Louisiana to meet emergency personnel who’ve been laboring to restore power and tend to thousands of evacuees from flooded lands in the aftermath of Hurricane Isaac last week.

Romney, meanwhile, said the Labor Day holiday marked “another day of worrying” for too many Americans anxious about finding a job.

Polls show the close race between two candidates with polar opposite political philosophies, especially on the economy, depends on who can convince a majority of voters they can lead the U.S. out of the stubborn economic doldrums, a weak recovery from the recession and 8.3 percent unemployment.

Those polls show most Americans continue to fault Obama’s Republican predecessor George W. Bush as author of the economic malaise. Most Republicans, however, blame Obama for failing to turn things around during his 3 ½ years in the White House.

Romney, polls show, is favored as the best candidate to handle the economy, although Obama is seen as the more likable choice.

Romney hit the economic theme hard in a statement marking Labor Day as “a chance to celebrate the strong American work ethic,” adding: “For far too many Americans, today is another day of worrying when their next paycheck will come.”

Obama’s backers were up early to try a morning do-over of his supporters’ less-than-rosy answers Sunday when asked to answer the classic campaign question: Are Americans better off than they were four years ago?

“Absolutely,” said Stephanie Cutter, Obama’s deputy campaign manager, speaking on NBC television. “By any measure the country has moved forward over the last four years. It might not be as fast as some people would’ve hoped. The president agrees with that.”

Martin O’Malley, Maryland’s Democratic governor, had answered the same question with a “no” on Sunday before turning the blame to Bush. Appearing Monday on CNN, O’Malley tried a more positive turn of phrase, saying, “We are clearly better off as a country because we’re now creating jobs rather than losing them. But we have not recovered all that we lost in the Bush recession. That’s why we need to continue to move forward” under Obama.

Romney was staying largely out of view for a few days, ceding the political attention to his rival and preparing for the October debates as Democratic conventioneers gathered for the opening of their event Tuesday in Charlotte, North Carolina.

Vice President Joe Biden joined the fray, accusing Republicans of seeking to undermine Medicare, the decades-old federal program millions of seniors rely on for health care. “We are for Medicare,” he said. “They are for voucher care.” That was a reference to a proposal in Congress by Rep. Paul Ryan, the Republican vice presidential nominee, to offer future retirees the option of buying private health insurance with a government subsidy.

Romney spent Sunday at his New Hampshire vacation home, leaving only to attend church services with his wife, Ann. Aides said he would spend much of the Democrats’ convention week preparing for three debates with Obama, beginning on Oct. 3.

At the Democratic convention, San Antonio Mayor Julian Castro, a rising start in the party, delivers the keynote speech on Tuesday, followed by first lady Michelle Obama’s remarks. Obama and Biden will be nominated for second terms on Wednesday night, when former President Bill Clinton takes the stage as star speaker. Biden and Obama close the convention Thursday night with their acceptance speeches.

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Associated Press writers Steven R. Hurst, Calvin Woodward, Philip Elliott, Michael Biesecker, Mitch Weiss, Beth Fouhy and Ken Thomas contributed to this story.