Sen. Sherrod Brown (D-Ohio), seen here meeting with coal miners in Martins Ferry, Ohio, stands out in Congress for both his progressive politics and his raspy growl. “He sounds like a working man,” says one supporter. (Dustin Franz/For The Washington Post)

Editor’s note: A previous version of this story omitted statements from Sen. Sherrod Brown in which he expressed uncertainty over whether his inclusion in the 2016 ticket would have resulted in a Democratic victory. The story has been updated to reflect his views more fully.

They could hear him before they could see him — that low, rumbling outboard motor of a voice. It could only be Sen. Sherrod Brown.

“Oh, that voice,” said Jose Arroyo, a third-generation steelworker, as it reverberated through the union hall. “I love that voice.”

Brown doesn’t know how he ended up sounding that way. It wasn’t from smoking or drinking, he says; maybe all those years of yelling at the Cleveland Indians on TV. His laryngologist routinely sticks some awful thing down his throat but hasn’t found anything wrong with him yet. And politically speaking, it’s his voice that’s keeping him healthy.

“When he talks to you,” said Arroyo, now a union rep, “he knows the language. He sounds like a working man.”

The Democratic senior senator from Ohio arrived at United Steelworkers Local 1375 for a roundtable discussion on trade in a pressed suit (made just 12 miles from his house by union workers, he’ll have you know) that belied his second-only-to-Bernie Sanders reputation as “rumpled,” paired with black Velcro shoes that did not. His hair was a thicket of gray and white.

He’d been coming to union halls such as this since he first ran for office at 21, long before his voice started to sound, as Sen. Al Franken (D-Minn.) says, as if he’d been hit in the throat by a hockey puck. He’s fluent in pension plans, overtime work rules and what he calls the “myths” of free trade. It’s what helped one of the most progressive members of the U.S. Senate win this county, Trumbull, with 63 percent of the vote in 2012 — the same place where Trump would score a six-point victory.

In an alternate universe where Hillary Clinton picked Sherrod Brown as her vice-presidential candidate, which she almost did, the Democratic ticket could have won Ohio, Wisconsin, Michigan and the White House.

“I don’t pretend that my being on the ticket would have made her win. I don’t know. I mean, if I had gone to Wisconsin and Michigan a lot, anything would have changed those two states,” he said in an interview with The Washington Post. “My wife thinks we would have won. She thinks we would have won Ohio.”

But instead of settling in to the Eisenhower Executive Office Building, Brown finds himself up for reelection in a state redder than the president’s face during an anti-CNN tweetstorm. His party, desperate to figure out a way to win back Rust Belt voters, will be scrutinizing this race like a laboratory experiment. If Brown pulls it off — well, perhaps they aren’t as doomed as some think.

The senator took a seat in a cavernous main room with chipped marble floor and fluorescent lights. He noted that Trump talked a big game on manufacturing — but that he had come here today mostly to listen.

“All too often we feel like no one listens to what we have to say,” said John Moliterno, a local councilman. “So thank you for coming.”

Listening may not be enough for Brown to hang on to his Senate seat. But it’s a good place to start.

“People keep asking me how I’m going to win back the Trump voters” Brown said. “Well, I don’t think I’ve ever lost them.”

Brown on the campaign trail with Hillary Clinton at a diner in Athens, Ohio, in May 2016. He says he offered to spend all his time campaigning in the Rust Belt if picked as her running mate. (Maddie McGarvey/For The Washington Post)

Sherrod Brown never wanted to be vice president, until one day he did.

“I have zero interest in being vice president,” he told The Post in 2015.

“He’s not running for vice president, Chris,” Brown’s wife, Pulitzer Prize-winning newspaper columnist Connie Schultz, told Chris Matthews on MSNBC. “No matter how many times you champion him to do so.”

Yet for all his protestations, the Clinton team saw Brown as a definite possibility, who might help win over white working-class voters, especially men. So whether out of a sense of duty or secret ambition, Brown decided to go through the vetting process.

“It was pretty uncomfortable,” he said.

“It was excruciating,” Schultz said.

Both Brown and Schultz spent nearly three hours locked in a room with lawyers, answering deeply invasive questions. They were asked about their acrimonious divorces from their first spouses. They were asked about decades worth of finances and every public statement they ever made. They were asked to share all their social media passwords. (That one, Schultz declined.)

“Jesus, this is one hell of a process,” Brown recalled telling one of the investigators during a bathroom break. “I’ve seen a lot worse than you,” the lawyer replied.

At the time, Brown didn’t publicly acknowledge his participation in the veepstakes. But that doesn’t mean he wasn’t gunning for the job.

“By the end, I really wanted it ” Brown said recently. “Because that’s human nature.”

He relished the idea of campaigning in the Midwest, he says now, and offered to live out of a bus that would spend all its time in Western Pennsylvania, Ohio, Michigan, Wisconsin and Iowa.

Three days before the selection he heard from “someone who knows this process” that it was down to him and Sen. Tim Kaine of Virginia. Later, after Kaine was unveiled as the No. 2, Brown says he heard from a former high-ranking Democratic official that Clinton had initially picked him but changed her mind.

A key factor: Clinton didn’t want to give Ohio’s Republican governor, John Kasich, the chance to appoint Brown’s replacement in the Senate. They worried that Brown might be the only way to keep the seat in Democratic hands.

Now, they get to find out.

Sherrod Brown, then a congressman, and his wife, Connie Schultz, then a columnist for the Cleveland Plain Dealer, in 2006, a couple of years after they wed. She says now that they are often asked if he will run for president. (Katherine Frey/The Washington Post)

Brown spent the day after the presidential election reading about trees. It was his birthday, but he didn’t feel like celebrating, and Schultz had bought him a book titled “Urban Forests.” If he read closely he would have learned about how even trees that have flourished for centuries have faced mortal threats. That, for example, in the early 1900s, the American chestnut was nearly wiped out by a blight and that one of the first warning signs was a mysterious orange fungus on the bark. Removing the diseased trees didn’t work. To save the forests, scientists injected them with a fungus of their own.

The book was a good respite from a devastating loss that, despite having his ear to the ground among Donald Trump’s “base,” Brown admits he never saw coming.

It’s an oversimplification, of course, to say that Trump became president because of the white working class. In fact, most of Trump’s voters were richer than the average American. But the Democrats’ difficulties winning working-class votes in the Midwest was a real problem, with no clear solution.

“It’s not out of the question that in 2020, if nothing changes, Democrats could win the popular vote by 5 million and lose the electoral college because of the Great Lakes states,” Brown said.

So, because many of his constituents voted for Trump — and, frankly, because it seemed like a good reelection strategy — Brown’s first instinct was to work with the president.

He penned a letter asking the new president to make good on his promise to overhaul U.S. trade policy and renegotiate NAFTA — to prioritize American workers over foreign ones. The president responded with a hand-scrawled note: “Sherrod, great letter. I will never let down our workers.”

But while the senator from Ohio tried to move past the election outcome, the winner seemed to have trouble doing the same. About three months after the election, Brown took a call from Trump to discuss a “Buy American” initiative. To his surprise, the commander in chief spent much of their time discussing his victory in Ohio.

Brown at a roundtable on opiod abuse in Zanesville, Ohio, in early July. (Dustin Franz/For The Washington Post)

Brown understood the impulse, to a degree. After his own first election victory, it was all he wanted to talk about for several days. “But then I realized nobody cared,” he said. “So I stopped.”

Republicans are downright giddy about the prospect of unseating Brown. He’s far too liberal for the state, they’ll say in ads that will fill the airwaves within months. They’ll dredge up old footage of him on the Senate floor in which he almost appears to compare anti-union efforts in Ohio and Wisconsin to the work of Adolf Hitler. They’ll hit him for being “pro-regulation.”

And they’ll point out that the guy’s been running for office since he was a senior at Yale. Yale!

He certainly is one of the Senate’s most endangered Democrats. And if he loses, it could be the last anyone will hear from Sen. Sherrod Brown. But, if he wins . . .

“We are constantly being asked by others if he’ll run for president in 2020,” Schultz said. “In a way that we never have before.”

It happens in supermarkets, at the theater, over dinner with friends, and in on-the-record interviews like this one, over breakfast in Columbus.

And why not? Brown can make a case that he appeals to Trump voters, Clinton voters and Bernie Sanders voters — “a uniting figure in the party,” says former Clinton spokesman Brian Fallon, who could help move Democrats past the bad feelings of the 2016 primary. A guy who can make the case that he knows how to win in states where Democrats always seem to lose. He could make those cases, if he wanted to.

“I come from here, I know how to win elections here — I get all that,” Brown said. “But I just don’t want to do it.”

In other words, Sherrod Brown will never want to run for president. Unless, of course, one day, he does.

After his roundtable with the steelworkers, Brown jumped in his new black Jeep Cherokee to ride out to Martins Ferry, a small town on the West Virginia border.

The Jeep is new because a distracted driver smashed into and totaled his old one in October. Sitting in the hospital for a checkup after the crash (he was fine), Brown passed the time by writing a statement praising consumer-protection laws and thanking the union-run Jeep factory in Toledo for making such a safe vehicle — and using American steel.

“Even in a hospital bed, you’re always on message,” Sen. Sheldon Whitehouse (D-R.I.) said when he reached Brown by phone.

Brown knows, however, that lip service can get you only so far. Trump, for example, might have had some good talking points about American workers — points he will certainly make this week when he heads to Youngstown — but he still needs to make good on some promises. The president, however, did sign one bill into law recently that Brown was proud to have helped make happen: a measure to provide funding for coal miners who were on the brink of losing their health-care benefits.

Canary in a coal mine: Brown inspects a vintage flame safety lamp given to him by a retired miner at a meeting in Martins Ferry. (Dustin Franz/For The Washington Post)

So he drove along the Ohio River, through the miasma of power plants and the shells of shutdown steel mills, to the basement of another union hall, to meet with retired miners to celebrate a victory and discuss the next fights. Brown has always had a special affinity for coal miners. Instead of the traditional congressional pin, he wears a canary — symbol of the canary in a coal mine, a reminder of worker safety. (Sometimes people think it’s a beer stein, which Brown admits isn’t the worst thing for relatability purposes.)

“A lot of miners voted for Trump because they thought he cared,” said Dave Dilly, a third-generation coal miner, as he clipped one of Brown’s canaries onto his camouflage Vietnam Veteran hat. “Who knows if he does, but we don’t have to wonder about Senator Brown.”

Afterward, a retiree named Tom Kacsmar presented Brown with a present. It was an old safety flame lamp, a silver relic still smudged with black soot and covered in dents — an early replacement for the gruesome practice of lowering birds into mines to see if there was sufficient air.

There was always danger down in the mines, but a skilled operator with the right tools had a better chance of surviving than most. Kacsmar thought Brown could use one on his Senate desk.