Barack Obama looked scary.

As darkness fell on South High Street, the cardboard cutout of the president, grinning in a dark suit with folded arms, stared out from the window of a shabby house like a Halloween decoration. Few people walked down this stretch of the long and broad artery that connects Columbus’s scrappy working-class neighborhoods to its corporate downtown and its restaurant-dotted college district. And none walked up to the house’s wooden door, which had a welcoming message taped to it.

“Please Come In,” it said.

Below that, a red, white and blue sticker added, “Ohio Votes Early. Register to Vote Here.” On Tuesday, the U.S. Supreme Court declined a challenge to the state’s in-person early-voting program — a big win for the Obama campaign, which has argued that minority and poor voters take advantage of such voting.

Inside this campaign office — one of many throughout the state — scattered signs promoted “Early Voting in Person!” A “Get Out the Vote Leadership Manual” sat on a desk under a handmade banner that read “Canvassing.” In the next room, a whiteboard reminded volunteers of “weeks to go” and kept track of calls made, doors knocked upon, voters registered. On a recent evening, two college-age volunteers hovered over their laptops. The one with chunky hipster glasses did data entry. The one with torn skinny jeans cut labels reading “Not just for some of us.” They didn’t seem the ideal people to reach the “us” — white, blue-collar swing voters — that will likely determine the presidential election.

The past month has been a period of wild swings in the presidential race. First there was the Democratic high after the party’s national convention and the certainty of party loyalists that Mitt Romney, President Obama’s Republican challenger, was dead in the water. Then came Obama’s disastrous debate performance in Denver that convinced many of his supporters that all was lost. Some swing states where the president had enjoyed a solid lead started to shift rightward. The president’s supporters took to rending their garments, and Romney worked lines into his stump speech contrasting Obama’s slide with his own surge. “A crescendo!” he called it.

In the middle of all this turmoil sits Ohio and its white working-class voters who may well decide the election.

Sen. Rob Portman (R-Ohio), who traveled with Romney to Hofstra University for the second presidential debate, told reporters on Tuesday that Ohio was “a dead heat.” Some reporters expressed skepticism, but Portman said that private, internal campaign polls had shown Romney making up a lot of ground since the first debate. Obama campaign manager Jim Messina immediately rebutted this assertion: “We’re winning in Ohio.”

While both sides seek to play the expectations game, Ohioans have already started casting votes. Franklin County, which includes Columbus, leads the state in absentee ballots returned; 76,371 have voted in the county, according to the Board of Elections. That’s about 13.5 percent of the total vote cast in the county in 2008, when Barack Obama received some 305,000 votes there, about 100,000 more than Republican candidate John McCain.

In Ohio, union leaders are organizing their troops to ensure the same result this time. They remind those dependent on the auto industry that the president fought to save it. The Obama campaign is sending in a dynamic duo of middle-class heroes — Bill Clinton and Bruce Springsteen — to the Cleveland suburb of Parma.

Portman has appeared outside his family’s Golden Lamb Inn, the oldest hotel in Ohio, in the southeastern city of Lebanon. As Romney stood at his side, his palms flat against his thighs, Portman implored conservatives, “Would you please vote early?”

In Columbus, at the foot of the ramp leading up to 104 South expressway, sits Dan’s Drive In, a classic American diner where locals trickled in for the gravy-doused roast beef and potatoes. Jerald Fridley, an 80-year-old retired truck driver, took a seat by the window across from his wife Phyllis, a 72-year-old retired school cafeteria worker.

“I’ve already voted,” Fridley said, adding that he and his wife had waited out in the rain last election and preferred to stay dry. Fridley said he had voted Republican most of his life, from Eisenhower through George H.W. Bush. But then Bill Clinton came along, convinced him Democrats could build a better economy, and then George W. Bush came along and convinced him that Republicans could not. Barack Obama, he said, convinced him that things could be different, and he hadn’t given up that hope. “I thought: ‘Give the guy another four years. He was left with an awful mess. He isn’t going to fix it overnight.’ ”

The couple commiserated over Obama’s anemic debate performance (“We don’t know what happened. He just wasn’t there,” Phyllis said.) As for Romney, who had arrived in Ohio for another campaign sweep only hours earlier, Jerald said, “he’s blowing hot air.”

“The 47 percent can go to hell?” Phyllis added. “I thought, ‘Never.’ ”

A few tables away, under the ceiling fans and 1950s-style stainless steel, John Thompson, 68, finished up his bean soup. He and his wife, Karen, took care of their bill and said that it is important that the government take care of its citizens. “Romney doesn’t give the impression that he cares about working people,” said Thompson, a carpenter. He said that he and his wife had absentee ballots ready for mailing on their desks back home. “What Romney’s saying is that we are just a bunch of moochers!”

As fire engines raced toward the highway, families across the street shopped under the fluorescent lights of the Volunteers of America thrift store. Used gloves for 99 cents hung from racks loaded with used T-shirts, dresses, pants and shoes. In the back, two men looked over a stereo with tape decks.

“You see where I’m shopping? I can’t afford to buy anything new,” Mary Skinner, 59, said as the cashier stuffed the pants, an umbrella and a yellow blanket she had selected into translucent plastic bags. The nursing home at which Skinner worked had frozen pay for the past three years, a development she attributed to cuts in Medicare. But that didn’t make her more likely to vote for Obama, she said. She hadn’t paid attention to the debate about Medicare, which Obama says he would protect from Romney’s proposed reforms. “I won’t vote for Obama,” she said, pausing to instruct her granddaughter Brianna to hit the gumball machine into which she had fed quarters.

Skinner is the sort of disaffected voter whom Romney is desperately trying to attract in Ohio. She said she had the sense that Romney was a competent manager who could fix things. But she also said, “I don’t think I’ll vote.”

In the sleepwear aisle, Diana Ooten, 29, with long bleached hair falling on her Lynyrd Skynyrd T-shirt, examined racks of undergarments. Her young son, Giovanni, ran over from the adjacent used-toy department clutching a plastic register.

“Mommy, I want to buy this one,” he implored. “I want people to come with money.”

“Okay, but that’s the only one,” she said.

Ooten, a single mother of four, had recently risen out of homelessness and off welfare, finding a part-time seasonal job loading and unloading trucks at a local bargain outlet. She expressed disdain for Romney, who she said had no idea what people like her go through, and said he had “no grasp of what he’s talking about” when it came to Planned Parenthood.

Describing herself as opposed to abortion, Ooten said that she had turned to the women’s health provider for early pregnancy tests that allowed her to get her newborn children on government insurance. She said she had used her time on welfare to better herself, and that food stamps helped her survive. Romney, she said, “thinks everyone is using it to sit there and be lazy.”

Ooten said she would vote for Obama — “but it’s not an election I am excited about.”

But not everyone who lives or works or plays on High Street is an Obama supporter.

Dylan Lane, a heavyset 25-year-old, romped with his corgi, Sprocket, on the lawn in front of Cap Party Supplies. Lane said he ran the store, but also owned a business called Nichols Sign and Banner. “I have two businesses that are failing,” he said, blaming excessive taxation. The president, he added, had no business experience; Romney did, and would get his vote.

Next door, motorcycles were parked in front of the porch of Double Ds Pub, where a couple of guys nursed an icy pail of Bud Lights. An auto mechanic who gave his name only as George (“only give my last name to people with badges and guns”) alternated between pulls of beer and drags on his Marlboro. “Anyone but Obama,” he said. “Government doesn’t create jobs. It sucks away jobs.”

A few miles north, the real estate signs advertising “Price Reduced” fade away and downtown’s office buildings and hotels rise up. Further north still, they give way to a fashionable district with boutiques, restaurants with valet parking and bars advertising “artisanal cocktails.” At a packed bar named Bodega, popular with students from nearby Ohio State University, people smoked cigarettes and drank dark beers and expressed disdain for Romney. “He hates women!” Samantha Dixon, a recent OSU graduate, shouted to her friends. One of them, Carlina Di Russo, a communications major with red lipstick stains on her cigarette, said there was “so much” activity around campus for Obama. For Romney, she said there was “not much.”

But even in the city’s liberal bastion, where people talked more about LGBT issues than jobs, people were split. Two couples were chatting outside the popular ice cream parlor Jeni’s, and all but one person in the group supported Romney. The holdout was Greg Beeman, a 28-year-old manager at a Whirlpool plant. He understood the points made by his wife and friends, one of whom worked on Romney’s 2008 campaign, but he still leaned toward the president.

“We just had this discussion at dinner,” Beeman said. “I don’t think anybody would have performed well in the last four years.”