TOLEDO, Ohio (Bloomberg) -- President Barack Obama said his "bet" on America's auto industry is paying off and that letting "Detroit go bankrupt" would have led to another Great Depression, drawing attention at a Labor Day rally in Ohio to Republican Mitt Romney's opposition to the rescue.
"If we had turned our backs on you, if America had thrown in the towel like that, GM and Chrysler wouldn't exist today," Obama told more than 3,000 people in Toledo, emphasizing that he led the 2009 rescue of the two U.S. automakers.
Heading into the Democratic National Convention this week in Charlotte, N.C., Obama has been barnstorming election battleground states -- Iowa, Colorado, Ohio and Virginia -- all of which he won in 2008 and where he's locked in tight contests with Romney.
Gallup polls find no sign yet that the Republican National Convention in Tampa, Fla., last week provided a bounce in support for Romney. Only 38 percent rated his Aug. 30 nomination acceptance speech good or excellent, the lowest favorable response to any of the acceptance speeches Gallup has tested since Republican Bob Dole's in 1996.
Gallup's daily tracking poll through Sunday showed the presidential race at 47 percent for Obama to 46 percent for Romney. Obama has held a one-point edge since Aug. 28. The Gallup poll on impressions of the convention was taken Aug. 31 through Sept. 1 and has a margin of error of plus or minus 4 percentage points.
Monday marked Obama's 27th visit to Ohio, where the unemployment rate of 7.2 percent in July is the lowest in the state since September 2008.
The state's unemployment rate is below the national jobless rate of 8.3 percent. Obama started his day having breakfast at a local diner with three autoworkers.
Obama's aides credit the auto rescue with playing a significant role in Ohio's job growth and spotlight Romney's opposition to the federal bailout of General Motors Co. and Chrysler Group LLC to try to hurt the Republican ticket with working-class voters. Romney wrote in a Nov. 19, 2008, opinion piece in the New York Times, under the headline "Let Detroit Go Bankrupt," that if the industry was bailed out, "you can kiss the American automotive industry goodbye."
Obama peppered his remarks with sports terms, shooting back at Romney for during the weekend likening the president to a coach who's had a losing season and should be fired.
"I've got one piece of advice for you" about Romney's "game plan for Ohio -- punt it away, it won't win the game," Obama said. "You don't need that coach, it's a losing season."
Commenting on Obama in Ohio on Sept. 1 Romney said, "If you have a coach that's zero and 23 million, you say it's time to get a new coach." The former Massachusetts governor was referring to the number of unemployed and underemployed in the U.S.
The auto bailout and tax policy are two of the policy differences with Romney that Obama is emphasizing in campaign events running up to his party's convention, which kicks off tomorrow.
As delegates gathered in Charlotte, union activists convened a Southern Workers Assembly at a local Baptist church, where speakers criticized both parties and the nation's organized-labor movement for failing to unionize workers in the South.
"Both parties have failed the working class," said Saladin Muhammad of the Southern International Worker Justice Campaign.
Campaign officials said Obama's Sept. 6 nomination acceptance speech will stress a different path for the U.S. economy than Romney is proposing. Without mentioning former President George W. Bush by name, Obama has been aligning Romney's fiscal policies with those of the previous administration, linking them to the worst recession since the Great Depression.
Obama will deliver his speech at the Bank of America stadium in Charlotte, an outdoor sports arena, despite a weather forecast that calls for a 50 percent chance of rain, according to his campaign spokesman.
"It will be there rain or shine," Ben LaBolt, Obama's spokesman, told reporters Monday in Charlotte.
After his Ohio speech, Obama traveled to LaPlace, La., outside New Orleans, to survey flood damage from Hurricane Isaac. Romney visited Louisiana on Aug. 31 for the same reason.
Romney and his wife, Ann, are spending the holiday at their vacation home on Lake Winnipesauke in Wolfeboro, N.H., and have no public events scheduled.
The Republican nominee was scheduled to spend most of the week in Vermont, preparing for his debates next month against Obama. Romney's running mate, U.S. Rep. Paul Ryan of Wisconsin, is campaigning in Greenville, N.C., and will stump Tuesday in Ohio and Iowa.
Vice President Joe Biden spoke at a Labor Day rally in Detroit, where he echoed Obama's attack on Romney.
"Folks you can't say you're going to create jobs in the United States of America when you're willing to let 1 million jobs go under with the liquidation of the automobile plants," Biden said.
Romney's campaign responded to the attacks by sounding its main message -- that American's aren't better off than they were four years ago -- and said the middle class has fared worse under Obama.
"The Obama campaign now has a clear message for Americans - you're doing well, you just don't know it," said Amanda Henneberg, a Romney campaign spokeswoman. "Americans deserve a president who understands we're not better off."
The Republican National Committee started its "Obama Isn't Working" rapid response center in Charlotte with a Web site and daily news conference "highlighting how America is not better off under president Obama."
"The president is going to be on defense, desperately trying to paper over the dismal record and make struggling Americans forget about their problems," RNC Chairman Reince Priebus told reporters.