Before a crowd of a few thousand Ohioans gathered at an airport hangar in the town of Vidalia, Republican presidential nominee Mitt Romney vowed on Tuesday that he would not allow President Barack Obama to secure a second term.

 

“We cannot afford four more years of Barack Obama," Romney said. “We’re not going to have four more years of Barack Obama.”

The first piece of that sentence is an essential campaign theme of Romney, that Obama cannot be trusted after leaving a legacy of stagnant job growth and bloated government. But conditions in Ohio suggest that the second piece is becoming increasingly unlikely.

The electoral map has evolved rapidly over the last two cycles, with demographic shifts putting states like Colorado, New Mexico and Virginia in play. But Ohio remains a mainstay of presidential politics, a bellwether that no Republican has lost without also losing the race.

Romney and running mate Paul Ryan are traveling across the state this week in a push to galvanize voters there, but there are emerging signs that the state's 18 electoral votes are slipping out of their grasp.

A new Quinnipiac University/New York Times/CBS News poll is the latest data point suggesting that Ohio is gravitating toward Obama, finding that Romney is lagging behind Obama 53 to 43 percent. That ten-point deficit is outside the margin of error.

That finding affirms a Washington Post poll, released on Tuesday, that gave Obama an eight-point lead among likely Ohio voters, 52 percent to 44 percent. 

Obama may be benefiting in part from Ohio's 7.2 percent unemployment rate, almost one full percentage point below the national average, which belies Romney's central campaign theme that Obama has been a poor economic steward. An advisor to Ohio Governor John Kasich, a Republican, faulted Romney on Tuesday for not shifting his message in the state.

"Romney would do better if he stood on John Kasich's shoulders and said, 'Here's an example of a state that's doing better with job creation, in spite of what the president is doing,'" Rex Elsass told CNN. "When you run advertising here that's running in the rest of the country, it's inconsistent with how people are feeling about Ohio -- that things are getting better."

The president's support for a bailout of the auto industry also appears to be a factor, with respondents to the Washington Post poll saying by an overwhelming majority that the bailout had been "mostly good" for the state. 

But Romney has also struggled to present a positive image to voters as his campaign grapples with the release of a tape in which Romney told private donors that 47 percent of the country was dependent on government aid. More Ohio voters viewed him unfavorably than favorably in the New York Times poll, by a 49-41 margin, compared to a 54-43 favorable to unfavorable split for Obama.

Voters surveyed by the Washington Post poll also gave Obama a commanding 23-point lead in response to a question about which candidate better understand the “economic problems people in the country are having." 

Romney has three separate campaign event scheduled in Ohio on Wednesday, part of a concerted effort to keep the state in play. But as the Romney-Ryan Ohio bus tour rolls on, they appear to face lengthening odds.