President Obama holds a small but significant lead in the perennial battleground state of Ohio, where a victory could spoil any chance for Mitt Romney to win the White House.

No Republican has won the presidency without winning Ohio, and Obama has been on a mission to keep the state’s 18 electoral votes in his column. His trip Wednesday to Akron and Mansfield was his ninth to the state this year and 24th since entering the Oval Office. 

The RealClearPolitics average of polls shows Obama with a 4.8 percentage point lead over Romney, an advantage further emphasized by a Quinnipiac University-CBS News-New York Times poll published Wednesday that showed the president with a 6-point edge in the state. 

While conservative pollster Rasmussen Reports found Obama with only a 2-point lead earlier this month, the pattern seems clear: Obama has an edge in perhaps the most critical state in the nation.

Democratic strategists and independent political observers credit Obama’s advantage to his support for the auto bailout and strategy of appealing to blue-collar workers. They also note that Ohio’s 7.2 percent unemployment rate is a full percentage point lower than the national average. 

“Romney is going to have to do something very unusual to take Ohio away from the president,” said Jim Friedman, a Cleveland lawyer whose involvement with the state’s Democratic Party has spanned several decades. 

Obama “is not doing great in Ohio, but he’s doing well enough,” said Peter Brown, the assistant director of the Quinnipiac University Polling Institute, who helped conduct the latest poll. “Obviously these numbers are good for him, and if the president wins this state, he’s going to get reelected.”

The auto bailout is perhaps Obama’s trump card in Ohio. 

Friedman argued Obama’s support and Romney’s opposition to the bailout are resonating in Ohio, where the car industry “is both historically and psychologically important.”

“Even though the automotive industry in Ohio is much smaller than it once was, Ohio voters still think of it as critically important,” he said.

Obama campaign spokesman Frank Benenati claimed that as many as 1 in 8 jobs in Ohio was dependent upon the car industry, whether directly or indirectly.

Jen Psaki, a spokeswoman for the Obama campaign, asserted that the bailout had salvaged 2,200 jobs in Ohio dealerships.

The industry is especially important in the northern part of the state, where Obama’s campaign is counting on a heavy turnout.

Romney is trying to battle Obama on the bailout, and on Wednesday his team released a new TV ad featuring an Ohio car dealership owner, Al Zarzour, who blames the bailout for forcing the closure of General Motors dealerships like his.

Curt Steiner, a Republican strategist in the state, insisted that Romney continues to hold a strong hand there.

“I think the polls show the race is competitive. I expect it to remain competitive, and I think that is a good sign for Gov. Romney,” he said.

Steiner downplayed the importance of the auto bailout.

“I think that will remain an issue, but people are going to look forward,” he said. “The argument over who did what to bail out what industry is not going to decide this election.”

Instead, Steiner argued, the economy remained a significant weak spot for Obama, with any recent improvement in Ohio not trumping the more general bleakness.

Almost everyone agrees the stakes in Ohio could hardly be higher for Romney.

“It he loses Ohio, it almost certainly means he loses Pennsylvania and Michigan, which are states that don’t lean Republican as much as Ohio does,” said David Cohen, a political science professor at the University of Akron.

“If he were to lose Ohio, it would be absolutely devastating to his chances of winning the presidency.”

Armed with good news from the recent polls, Obama went to the Buckeye State on Wednesday and hammered his opponent’s tax plan, which he said would mean that middle-class Americans would pay more each year.

“If Gov. Romney wants to keep his word and pay for this plan, then he’d have to cut tax breaks that middle-class families depend on,” Obama said at a campaign stop in Mansfield, Ohio. “He’s asking you to pay more so that people like him can get a big tax cut.”

House Speaker John BoehnerJohn Andrew BoehnerA warning to Ryan’s successor: The Speakership is no cakewalk With Ryan out, let’s blow up the process for selecting the next Speaker Race for Republican Speaker rare chance to unify party for election MORE (R-Ohio) showed little anxiety about Romney’s chances in his home state when he was asked Wednesday whether the Quinnipiac-Times polls concerned him.

“There’s one fact, one fact, and that is the president’s economic policies have failed and have actually made things worse,” he said.

“I believe that when people go to the polls in October and early November, it’s going to be a referendum on the president’s economic policies.”

Some experts, meanwhile, suggested that Obama’s apparent polling lead in the state was merely a passing trend.

The suggestion that Obama is up by around 5 points “just doesn’t ring true to me,” said Alfred Tuchfarber, a political science professor emeritus at the University of Cincinnati with a specialization in polling.

Tuchfarber noted that national polling basically suggested that the race was a dead heat.

Ohio has long tended “to be 1 percent to 3 percent more Republican than the nation as a whole,” he added. “If nothing fundamental has changed in Ohio, I just don’t believe Obama is ahead by 5 points.”

Even Brown, the Quinnipiac pollster, cautioned on Wednesday that the poll numbers could still move in the coming months, particularly after the conventions.

“The big stuff is yet to come,” he said. “History has shown they can move a lot.”