MANSFIELD, Ohio — It’s all about Ohio — again.

The economy has improved here, and so has President Obama’s standing, putting pressure on Republican Mitt Romney in a state critical to his presidential hopes.

No Republican has won the White House without winning Ohio, and Romney hopes to catch Obama here by slashing at his jobs record in working-class regions.

“America doesn’t have to have the long face it has had under this president,” the Republican shouted Monday to a cheering audience in hard-scrabble Mansfield, just weeks after Obama visited. “We can get America rolling again, growing again.”

In a sign of the state’s importance, hardly a week goes without the candidates appearing in Ohio. Same goes for their running mates; Republican Paul Ryan was campaigning in the Appalachian southeast Wednesday, following a similar weekend trip by Vice President Joe Biden, who is to return to the state Wednesday.

Less than two months from Election Day, both parties say their internal campaign polling shows Obama with a narrow lead in Ohio, a Midwestern state that offers 18 Electoral College votes and has played an important role in determining every recent White House race.

Numbers tell the story of the high stakes and, perhaps, show why Obama has been able to maintain an edge — and why Romney remains within striking distance.

The candidates and supportive outside groups have spent a stunning $112 million on TV advertising in the state — one-sixth the total spent nationwide. And Obama and groups that support him have been outspending Romney and Republican-leaning independent groups here all summer, outpacing the GOP $2 million to $1 million last week alone. That’s despite Romney having tapped into his general election bank account last week to boost his ads here.

All year, the race here has been close. A Quinnipiac University poll in April after Romney locked up the Republican nomination showed a 1-point race among registered voters in the state. But two recent polls — Quinnipiac/CBS/New York Times in August and July — showed Obama up 6 percentage points among likely voters, and reaching 50 percent, a key marker for an endangered incumbent.

Both Republicans and Democrats say internal surveys show it tighter now, with Obama leading by about 3 percentage points.

Still, Democrats are almost giddy that Obama has been able to show strength in this manufacturing state, which suffered during the recession but has seen its unemployment rate fall from 7.7 percent in January to 7.2 percent in July.

On Monday, Romney blistered the president over deep defense cuts scheduled as part of a deficit-reduction proposal. Those possible cuts mean the city would lose its 179th Air National Guard unit, which would cost hundreds of jobs. That’s on top of a GM plant that closed in nearby Ontario, Ohio, two years ago.

“It will be bad for employment if it goes forward. It will also be bad for our national security,” Romney said, promising to block such cuts as president.

Here and elsewhere, Obama is working to spread a message of economic progress, despite a national unemployment rate stuck above 8 percent.

In Toledo last week, the president argued that his decision to bail out the U.S. auto industry in neighboring Michigan has fueled a manufacturing turnaround in the region. GM recently announced a $200 million expansion of its Lordstown, Ohio, plant, where the company’s best-selling Chevrolet Cruze is made.

It’s in this Midwest region where Obama reminds audiences that Romney wrote a Wall Street Journal opinion piece in 2008 suggesting carmakers declare bankruptcy and restructure. Although that’s what happened under the Obama’s administration, the Romney piece’s headline, “Let Detroit Go Bankrupt,” has been a bumper-sticker line for the Obama campaign.

“Do the folks in Ohio really think that Gov. Romney, with his views on outsourcing, with his views on General Motors and Chrysler and beyond that, do they honestly believe that if he had been president the last four years that today that there would be today 115,000 auto jobs in Ohio?” Biden said last weekend in Zanesville, 55 miles east of Columbus.

Countering, Romney tries to stoke doubt about the president’s economic competence, and he criticizes Obama on energy, specifically the administration’s regulations on coal mining and oil and gas drilling. Those issues resonate in southern Ohio.

It is all part of a two-fold Ohio strategy by Romney: suppress Obama’s edge in places like swing-voting northern and central Ohio while dispatching Ryan, from working-class Janesville, Wis., to widen the GOP ticket’s edge in towns along the Ohio River.

Romney seems to have an opening.

“The only driver here is the economy, and we’ve seen what Barack Obama has to offer,” said Andrew Kvochick, a 30-year-old lawyer from Lexington who voted for Obama in 2008. “We’d like to see what Mitt Romney has to offer.”