Senator Sherrod Brown, Democrat of Ohio, has always had the luxury of running for election in remarkably good years for his party. He won his seat in 2006, during the backlash to the Iraq War, won re-election in 2012, the last time a Democrat carried the state, and did so again in 2018, amid a national reckoning of Donald J. Trump’s presidency.
His campaign in 2024 will be different, and most likely the toughest of his career, with a Republican Party determined to win his seat and a Democratic president hanging off him like one of his trademark rumpled suits. In an election year when control of the Senate relies on the Democratic Party’s ability to win every single competitive race, an enormous weight sits on the slumped shoulders of the famously disheveled 71-year-old.
“I fight for Ohioans,” Mr. Brown said in an interview on Wednesday. “There’s a reason I win in a state that’s a little more Republican.”
Mr. Brown’s tousled hair and gravelly voice have spoken to working-class voters since he was elected Ohio’s secretary of state in 1982. His arms may be clenched tightly around his chest, but he projects a casual confidence that he can win once again in firmly red Ohio, where he is the last Democrat holding statewide office.
But beneath that image is trouble. On Monday, he had just received an endorsement from the 100,000-strong Ohio State Building and Construction Trades Council, when a retired bricklayer, Jeff King, pulled him aside in a weathered union hall in Dayton.
Mr. Brown has had plenty of achievements to run on, Mr. King, who made the trip from his local in Cincinnati, told the senator. But, he asked, would workers in a blue-collar state that has twice handed Mr. Trump eight-percentage-point victories understand who should get the credit?
“That’s the mission,” Mr. Brown said, leaning in. “They don’t know enough.”
The party and its union allies have made the re-election of Ohio’s senior senator their highest priority — “the very top,” said Lee Saunders, the president of the American Federation of State, County and Municipal Employees and the chairman of the A.F.L.-C.I.O.’s political committee.
The election could be breaking Mr. Brown’s way. With Mr. Trump’s endorsement — and a nudge from a Democratic super PAC — the Democrats’ preferred Republican opponent, Bernie Moreno, easily prevailed in the Republican Senate primary on Tuesday, handing the incumbent a foil with staggering wealth, little political experience and the imprimatur of a former president who could prompt some voters to split their tickets.
The next day, the Biden administration announced an $8.5 billion deal to fund Intel Corporation’s semiconductor manufacturing, much of it destined for Ohio, courtesy of legislation that Mr. Brown helped secure. Because of Mr. Brown, that law, the Chips and Science Act, requires so-called project labor agreements to be struck between management and union laborers before plant construction could begin. So 7,000 union tradesmen will be employed at the massive Intel complex outside of Columbus.
On that same Wednesday, the administration finalized stringent new car and truck emissions standards that should increase electric-vehicle manufacturing at the Stellantis Jeep complex in Toledo and automotive battery plants around Youngstown.
Finally, construction should begin around election time on a long-sought replacement for the Brent Spence Bridge, linking Cincinnati to its suburbs in Kentucky. That, too, was delivered in part by Mr. Brown.
Yet Republicans are supremely confident for a much simpler reason: political gravity. In March polling, Mr. Trump leads Mr. Biden in Ohio by as few as nine percentage points, and as many as 18. Mr. Brown will most likely run ahead of Mr. Biden in the state, Republicans say, but not by enough to win.
“We have an opportunity now to retire the old commie,” Mr. Moreno proclaimed at his victory party on Tuesday, referring to Mr. Brown.
In an interview on Wednesday, Mr. Brown insisted that his toughest Senate race was his first, when he unseated Mike DeWine, who went on to win two terms as Ohio’s governor.
And Mr. DeWine lent credence to that confidence on Monday night, pleading with voters in Columbus to cast their ballots for the candidate he thought could beat Mr. Brown, State Senator Matt Dolan.
“This is not going to be an easy race, folks,” Mr. DeWine advised at the Hey Hey Bar & Grill in Columbus’s German Village. “I’ve run against this man.”
This year could be different.
“Nothing can save Sherrod Brown from the fact that he votes with Joe Biden 99 percent of the time,” Mr. Moreno said.
Compared to Mr. Moreno, a political newcomer, Mr. Brown is a fixture in Ohio. “People just know I stand up for them,” he said.
Two years ago, Tim Ryan, who was then a U.S. representative, ran for the Senate as a blue-collar Democrat from the Mahoning Valley, cut from the mold of Mr. Brown. Though he ran what has almost universally been hailed as a textbook campaign, he lost to J.D. Vance by six percentage points.
But Mr. Ryan said he lacked something Mr. Brown has: a fixed identity across the state. To win in Ohio as a Democrat, he said, “the one thing you need to do is have the name Sherrod Brown.”
This fight will be about Mr. Moreno trying to define Mr. Brown’s policy agenda — and the Democrat removing Mr. Biden’s name from it. Mr. Brown talks up his action to save more than 1,460 pensions of union drivers in Ohio through the Butch Lewis Act, a pension provision named in memory of an Ohio Teamster and inserted into the enormous Covid relief law, the American Rescue Plan.
He tells audiences of his role in the huge law signed by Mr. Biden that extended veterans health care to former service members who were exposed to toxic “burn pits” in Iraq and Afghanistan. It was also named after an Ohioan, Sgt. First Class Heath Robinson, who died of lung cancer at 39.
He speaks effusively of the CHIPS Act, which ensures that the two new semiconductor plants being built in Ohio with federal money will employ union-trained workers.
But even he said he understood the road ahead, especially when Mr. Moreno was calling his record “job-killing, Green New Deal radicalism.”
“They know the accomplishments,” Mr. Brown said. “They just don’t really know who did it.”
The incumbent will almost certainly be able to match Republicans dollar for dollar and then some. Between the allegiances he has built in the labor movement and the corporate interests with business before the Senate Banking Committee, which he chairs, Mr. Brown has built a formidable war chest: $33.5 million raised since 2019, and $13.5 million cash on hand at the end of last month.
Mr. Moreno, after a brutal three-way primary, emerged with $2.4 million in cash, according to late February federal campaign finance records.
And Mr. Brown said beneath Ohio’s pro-Trump tilt was a state less conservative than Republicans believe. Last August, Ohioans crushed a ballot measure engineered by Republicans to make it harder for future ballot measures to pass, a transparent effort to defeat a pending vote on abortion rights. Three months later, they enshrined the right to abortion in the state’s Constitution, by 13 percentage points. On the same day, they voted to legalize marijuana — by 14 points.
“That ought to scare them,” Mr. Brown said of his Republican opponents. “They need to figure out how to win those voters.”
Just how much Mr. Brown can continue to outperform national Democrats is a subject of debate in Ohio. David Pepper, a former chairman of the Ohio Democratic Party, said the senator outperformed the rest of the Democratic ticket in 2018 by more than 10 percentage points, beating Republican James B. Renacci by 7 percentage points when Mr. DeWine was beating his Democratic opponent for governor, Richard Cordray, by 3.7 points.
“The question is, how much does Biden compete here?” said David Pepper, a former chairman of the Ohio Democratic Party. “If he competes hard, he keeps it in reach for Brown.”
At the Dayton union hall of the International Brotherhood of Electrical Workers Local 82, it was impossible to find anyone not firmly in Mr. Brown’s camp.
“As many pensions as he’s saved, absolutely” he’s going to win, David Bruce, the president of the Dayton Building Trades Council, declared.
But beneath the bravado was an acknowledgment of the work ahead.
“That’s our battle,” the retired bricklayer, Mr. King, said, citing the stream of right-wing information consumed by many of his union brethren. “We’re called as union leaders to do a better job with our message. The problem is, we’re bricklayers. We don’t understand messages.”