LIMA, Ohio — President Obama has made the federal bailout of the auto industry his central argument on jobs in this pivotal state.

On the air heavily last month was evidence: an ad displaying a map of Ohio and the auto jobs in nearly every corner of the state, along with criticism of Republican nominee Mitt Romney’s opposition to the bailout.

While making the point that the industry’s fate affected the entire state, the ad ran in areas with a higher concentration of auto jobs: Youngstown, Cleveland, Toledo and Dayton.

POLITICAL CARTOONS: Horsey’s Top of the Ticket

The presidential campaign is, by definition, a national race. But it’s also nine distinct campaigns in the battleground states, each with its own regional and cultural nuances, requiring deft calibrations of candidate messages.

In Ohio, the Obama and Romney campaigns have taken sharply different approaches. And their tactical choices help explain how Obama has built a solid lead in polls of Ohio voters, an alarming sign for Romney, who sorely needs the state’s 18 electoral votes.

Much of Obama’s rise in the Ohio polls is consistent with national trends. But as in other battleground states, public opinion in his favor is also being driven by the candidates’ ubiquitous local TV ads and news coverage of their frequent visits, among other things.

What voters see and hear varies widely among Ohio’s 88 counties, depending on voter-targeting moves by the campaigns.

Many of Ohio’s voters are scattered among major metropolitan areas with rich subcultures: Cincinnati, Cleveland, Columbus, Toledo, Dayton, Akron and Youngstown. What plays in Youngstown, a blue-collar town struggling for decades to recover from the decline of steel, can be off-key in Cincinnati, which in ways has more in common with nearby cities of the South than with Ohio towns along Lake Erie. Scattered across the state’s vast stretches of farmland are hundreds of small towns that bear little resemblance to their city cousins.

“It’s the difference between victory and defeat, knowing that the ads run in Toledo may not play well in southeastern Ohio,” said Greg Haas, who led Bill Clinton’s successful Ohio campaign in 1992.

Obama’s ad strategy in Ohio has been more elaborate than Romney’s, both geographically and demographically. One striking example is a series of Obama ads targeting women, who polls show as strongly favoring the president both in Ohio and nationwide.

The ads show Romney vowing to stop federal funding for Planned Parenthood, describe him as dangerous to women’s health and state (inaccurately) that he backs outlawing abortion “even in the cases of rape and incest.”

Obama has run the ads only in the Toledo, Cleveland, Columbus and Cincinnati media markets, reaching millions of suburban and urban women. He has kept the spots off the air in smaller media markets that serve more conservative rural areas — in parts of central, eastern and western Ohio — where they might create a backlash.

To avoid a backlash of his own among more moderate voters, Romney has steered clear of social issues in his TV ads in major markets in Ohio, instead focusing mainly on attacking Obama’s economic record. But in direct mail to conservative voters, his allies in the state Republican Party have highlighted Romney’s belief that life begins at conception, his opposition to same-sex marriage and his support of a bill in Massachusetts to let the Catholic Church deny adoptions to gay couples.

For Romney, direct appeals to conservatives on social issues are crucial, particularly in the Cincinnati suburbs where President George W. Bush crushed John F. Kerry in 2004.

“We’ve got to max out those numbers there,” said Matthew Borges, a former Romney aide who is now executive director of the state Republican Party.

Cincinnati’s media market is the one where Romney has advertised the most, roughly even with Obama. In Columbus, Cleveland, Dayton and Toledo, Obama has outspent Romney by a modest margin — not surprising since Romney, unlike Obama, had to dump a large sum of money into party primaries.

What is surprising is the Romney team’s decision to skip advertising until recent weeks in six smaller Ohio media markets, including Lima, Zanesville and Youngstown, all areas of economic distress where voters are also culturally distant from Obama. Stepping into the vacuum, the Obama campaign has advertised heavily in all of them for months, largely with spots attacking Romney.

Together, the smaller markets reach about 10% of Ohio’s television viewers, the bulk of them in Republican areas.

“For Romney to overlook those markets is unbelievable,” said Don Spicer, a veteran Ohio ad buyer for Democratic candidates who is not working for Obama. “If they’re not getting the Republican message and all they’re hearing is from Obama, that’s a problem for Romney.”

Just as Romney started advertising in those areas last month, Obama started running a radio ad in rural markets featuring John Glenn, a hero to many in small-town Ohio. The former astronaut and U.S. senator from Ohio plugs Obama’s plans for community colleges and small-business loans, saying he would give “every child from small-town America the same opportunities that I had.”

Romney’s team concluded it would have been too expensive to advertise sooner in Ohio’s smaller television markets when spots running in the larger ones could reach far more voters.

The Romney campaign started advertising statewide in Ohio last month. “Super PACs” aligned with Romney have supplemented his anti-Obama advertising in Ohio, but they have not placed their spots systematically in markets where Romney was off the air. Also, neither Romney nor the super PACs sympathetic to him have hewed to a consistent narrative, as Obama and his allies have.

The Romney campaign has, over the last few weeks, sought to take advantage of some of Ohio’s political variety by running ads attacking Obama’s record on coal in the small Appalachian media markets along the West Virginia border.

By blaming Obama for the loss of coal jobs, Romney is trying to pick up tens of thousands more votes in the area than Republican John McCain won four years ago. Among other things, Romney hopes to make Obama the first Democratic presidential candidate since George McGovern in 1972 to lose Belmont County.

POLITICAL CARTOONS: Horsey’s Top of the Ticket

michael.finnegan@latimes.com

One in a series of occasional stories on the states that will determine the next president.