DAYTON, Ohio — In one of the nation’s political bellwethers, the face of Republican aspirations to recapture the Senate is youthful, if not boyish. Josh Mandel, the 33-year-old state treasurer of Ohio, looks more like a candidate for class president than Congress.
But despite a 15-point disadvantage in the polls, Mandel — a two-tour Marine veteran of the Iraq War — is considered by political analysts to be an up-and-coming threat to liberal Democratic incumbent Sherrod Brown.
Republicans from around the country are pouring money into Mandel’s campaign, as Brown’s approval ratings sag along with Ohio’s economy.
The Ohio race is seen as fertile territory for Republicans in next year’s election, as the party attempts a second anti-Democratic wave that could help complete a takeover of Congress that began in 2010. The party needs to pick up just four seats to win a majority in the Senate.
Analysts say that 10 of the 23 contested seats held by Democrats or their independent allies are vulnerable to a Republican takeover, including in the crucial swing states of Florida and Virginia, as well as Ohio. Of the 10 Republican seats being contested, only two are considered vulnerable, including Scott Brown’s in Massachusetts.
“The numbers don’t lie, which is why you need to look at the Republicans as favorites to win a majority,’’ said Jennifer Duffy, senior editor of the nonpartisan Cook Political Report.
In Ohio, the Senate race is listed by Cook as still leaning in Sherrod Brown’s favor, but only slightly. Analysts say they expect the race to officially become a tossup by next year.
A first-term senator with $3.5 million in the bank, Brown handily won election in 2006 but has seen his approval ratings plunge below 40 percent. He has amassed one of the most liberal voting records in the Senate, according to the National Journal’s ratings, a distinction he shares with several colleagues, including Harry Reid of Nevada, the majority leader, and Bernie Sanders, a self-described socialist from Vermont.
“It’s probably going to be a huge sticking point for a lot of Ohioans. On average, we’re a center-right state, and it’s all about appealing to that average voter,’’ said James Holland, a political science professor at the University of Akron.
Some independent voters, turned off by his liberal voting record, have already defected, polls suggest. But Brown remains confident.
“I get up everyday trying to fight for jobs. That’s my mission, and the election will take care of itself,’’ he told the Globe.
As Ohioans continue to grapple with a sluggish economy, the most significant threat to Brown is illustrated on the streets of Dayton.
Residents have witnessed the decay of this once-dynamic manufacturing hub. Downtown is quiet, home to rows of vacant buildings and storefronts displaying “space for lease’’ placards. The unemployment rate is 11.6 percent.
Dayton’s population has dropped nearly 15 percent in the last decade, and it has lost a lot of jobs as major businesses have either shut down or moved. In 2008, General Motors closed its sport utility vehicle assembly plant in nearby Moraine, leaving 2,500 workers without jobs.
“We’re watching the death of our city,’’ said Tammy Minehart, 40, a registered nurse at Good Samaritan Hospital.
Minehart has voted for Democrats her entire life, including Brown in 2006. But she has grown disenchanted with a party that she says is “too focused on playing politics’’ as her hometown continues to crumble. It has swayed her to consider shedding an allegiance.
“I’m going to take a good, hard look at the other guy,’’ Minehart said.
Veronica Ferrette, 47, of Lyndhurst, another lifelong Democrat who voted for Brown, takes it a step further. “There’s no way in hell I’m supporting him again,’’ she said. “We have people out of work, long lines of unemployment, and Sherrod Brown hasn’t stepped up.’’
The senator’s most glaring shortcoming: “He takes his marching orders from President Obama,’’ Ferrette said.
After supporting Obama in 2008, Ohio voters are split 46-47 percent on whether he deserves reelection. His slumping ratings could be perilous for Democrats — including Brown — whose fortunes will probably rise or fall with the president.
“If the economy here continues to suffer, voters are going to blame the president. Then they’ll probably look down the ballot at Brown, see the D next to his name, and assign some of that blame to him,’’ Holland said.
With this in mind, Mandel presses ahead with his challenge, making every effort on the campaign trail to link Brown with Obama. At a fund-raiser last week, addressing an audience of nearly 40 conservative donors who sipped on cocktails and coffee in a local banquet hall, Mandel denounced Brown as “a loyal soldier of the Obama administration who can always be counted on to fall in line.’’
The treasurer later delighted the gray-haired crowd of baby boomers with calls to limit government intervention in the private sector, a pledge to only serve two terms if elected, and an assurance that their contributions to his campaign were in fact “investments’’ in their children’s and grandchildren’s future.
Though Mandel trails in the polls, he raised $2.3 million in campaign contributions from April through June, the most of any challenger in the country.
Mandel has served as a city councilor, state legislator and Marine, completing two tours of duty in Iraq’s Anbar province, where he worked as an intelligence specialist.
In November, he won his first statewide office to become treasurer after trouncing the Democratic incumbent by 14 points. His victory was set against the backdrop of a Republican revolution in Ohio, as they reclaimed the governor’s mansion, picked up five congressional seats, and won a significant majority in the state Legislature.
Despite the 2010 results, Ohio Democrats insist voters here have already soured on Republicans, especially as the state’s GOP is trying to push through a controversial law restricting collective bargaining rights for 360,000 public employees.
Democrats took to the offensive against Mandel even before the GOP primary, which he is expected to win handily.
They accuse him of using the treasurer’s office to aid his Senate campaign, and they question his failure to file with federal officials the required personal financial disclosures, which remain unfiled four months after the due date.
Democrats also cite a broken campaign promise from last fall, that Mandel would serve at least four years in his current position.
“The only job Josh Mandel cares about is his next one. His political ambition is so strong that he doesn’t care if he breaks the rules,’’ said Justin Barasky, a spokesman for the Ohio Democratic Party.
Given that independents make up a majority of the Ohio electorate, the Senate election may well come down to voters like Kathleen Diroll.
The 60-year-old Diroll, who works part time at Paradies store in Concourse C of Dayton International Airport, needs two jobs to stay afloat. “I also work as a housekeeper,’’ she said. “I used to have a housekeeper. Now I am one.’’
She has grown apart from the GOP — “It’s not my father’s Republican Party’’ — but she believes Democrats have squandered their chances. Undecided for now, Diroll will wait to see if the proof is in the economy.
“The only thing you can rely on is voting the issues,’’ she said. “That, and God, of course.’’Alex Katz can be reached at email@example.com.