President Barack Obama told Americans on Monday to punt away Mitt Romney's economic game plan, in a new swipe at his Republican rival on the road to this week's Democratic National Convention.
New polling data meanwhile suggested that Romney failed to score a significant "bounce" from his own convention in Florida last week, reflecting the tight race to November's election and a dearth of undecided voters.
Obama surrounded himself with union members in Ohio, the crucial swing state that Republicans must historically win if they are to reach the White House, on Labor Day, an annual holiday honoring achievements of US workers.
He also freshened up his stump speech with American football metaphors, playing off Romney's self-portrayal as a new coach that would lead the country to a winning season.
"The problem is everybody has already seen his economic playbook, we know what's in it," Obama said, accusing Romney and his running mate Paul Ryan of plotting middle class tax hikes and cuts in health care for the elderly.
"I have got one piece of advice for you about the Romney-Ryan game plan, Ohio -- punt it away, it won't work, it won't win the game. You don't need that coach, that's a losing season," Obama said.
Romney, who was in Ohio on Saturday on the first day of the US college football season, portrayed Obama as the coach of a losing team, and suggested himself as an alternative.
"It's time to get a new coach ... it's time for America to see a winning season again, and we're going to bring it to them," Romney said in Cincinnati.
Toledo is home to General Motors and Chrysler factories whose workers benefited from a multi-billion-dollar auto industry bailout championed by the president and opposed by Romney in 2009.
Romney chose not to campaign on Labor Day, which fell the weekend after the intensity of his own nominating convention in Florida, spending time with his family, and taking a turn on his boat near his New Hampshire vacation house.
But he issued a statement saying Labor Day was a chance to celebrate the strong American work ethic.
"For far too many Americans, today is another day of worrying when their next paycheck will come. Over 23 million Americans are struggling for work and job creation has not returned to our economy the way it should," Romney said.
"My plan for a stronger middle class will champion small businesses, create millions of good jobs, and build a better future for our country," he added.
Hopes in the Romney camp that his convention last week would help him nose ahead in the White House race were dimmed by new polling data by Gallup, showing little change in a deadlocked race.
Forty percent of adults asked over the last three days said the convention had made them more likely to vote for Romney in November's election, but a similar 38 percent said events in Florida made them less likely to back him.
Obama led the man trying to deny him a second term by 47 percent to 46 percent in Gallup's latest daily tracking poll.
Though cheered by polling data, Democrats were also trying to put out the latest campaign brush fire, after several top party figures struggled to answer on Sunday whether Americans were better off after four Obama years.
"Folks, let me make something clear, say it to the press -- America is better off today than they (Republicans) left us," said Vice President Joe Biden, campaigning in Michigan.
"Let me just sum it up this way folks ... Osama Bin Laden is dead and General Motors is alive."
But Ryan, in a raid into North Carolina ahead of the Democratic convention, drew comparisons between Obama and one-term Democrat president Jimmy Carter, who was felled by a poor economy.
"The president can say a lot of things, and he will, but he can't tell you that you're better off. Simply put, the Jimmy Carter years look like the good old days compared to where we are right now," Ryan said.
Obama is on a four-day "Road to Charlotte" tour taking in territory that will decide November's election, in which his prospects are clouded by a painfully slow economic recovery and a 8.3 percent unemployment rate.
He has already visited Iowa and Colorado and landed in New Orleans on Monday to tour areas stricken by Hurricane Isaac last week.
Obama will travel to another swing state, Virginia, on Tuesday, before flying into Charlotte, North Carolina, on Wednesday on the eve of his big Democratic National Convention address.
Thousands of Democratic party activists were already gathering in Charlotte ahead of the first night Tuesday of the nominating bonanza, which features an address by First Lady Michelle Obama.
Party officials said Obama's speech, to be held at a 74,000-seater stadium Thursday, would go on "rain or shine," despite a questionable weather forecast.