ERIE, Pa. — Harold Klinzing, a 46-year-old roofer who loves his labor union, is the sort of voter Democratic presidential victories were once built upon.

“I loved Bill Clinton,” Klinzing recalled fondly. “He was my favorite president. I loved him to death.”

But after voting for Barack Obama in 2008, Klinzing, a lifelong Democrat, had soured on him by 2012 and sat out that election entirely. It wasn’t until he started hearing about Donald Trump in 2015 that Klinzing felt excited about a politician again.

“I just absolutely love the way Trump presents himself,” Klinzing said during a recent lunch break while laying down a rubber roof on a high school in Union City. “I’ve always been brutally honest my entire life. I say what I think and if you don’t like me for it at least I’m honest, is the way I look at it. And Trump comes off that way.”

In this pleasant lakeside city at the far western edge of Pennsylvania, where residents can expect to be blanketed in eight feet of snow each winter, voting Democrat is a tradition that has been passed down through families, along with a union card. But in 2016, the ties between working class voters here and the Democratic Party snapped, helping Trump narrowly carry Erie County just four years after Obama won it by 16 points.

Voters like Klinzing jumped aboard the Trump train, raising questions in this former Democratic stronghold about whether Democrats can win back white working-class voters in Western Pennsylvania this time around amid a stronger local economy fueled by a regional construction boom.

“I just absolutely love the way Trump presents himself,’’ said Klinzing, a member of the Roofers Union Local 210. Craig F. Walker/Globe Staff

Klinzing said he’s open to coming back to his political home — but only once Trump has left office.

“I’m not going to say I’m going to be a Republican for the rest of my life,” Klinzing said. “When Trump’s gone, I’m going to go back to both sides. [But] Trump 2020 definitely has my vote.”

Pennsylvania By the numbers Compare to Erie County, Pa. How state voted in 2016 election 2012 election 2008 election Democrat Other Republican Democrat Other Republican Democrat Other Republican Demographics: Population 12,790,505 77.30% White

10.60% Black

6.80% Hispanic/Latino

0.10% American Indian/Alaska native

3.20% Asian

0% Hawaiian/Pacific Islander

1.80% Two or more races Unemployment rate in June 2019: 3.80% Median income: $56,951 Erie County, Pa. By the numbers Compare to statewide How county voted in 2016 election 2012 election 2008 election Democrat Other Republican Democrat Other Republican Democrat Other Republican City of Erie, Pa., demographics: Population 98,970 70.20% White

15.50% Black

7.50% Hispanic/Latino

0.30% American Indian/Alaska native

2.90% Asian

0% Hawaiian/Pacific Islander

3.20% Two or more races Unemployment rate in June 2019: 4.90% Median income: $35,802

Klinzing was taught the importance of a good union job by his dad, an assembler and union president at a tool factory called Reed Manufacturing. Voting Democrat and being in a union were often a package deal in a city that was ruled by organized labor.

But as factories and plants started to disappear from Erie in the 1990s, union power also waned, and the rank and file grew restless with the status quo.

“People are getting frustrated because there’s no industry,” said T.J. Sandell, a plumber and the president of the local building trades’ association.

T.J. Sandell, a plumber from Erie, is the president of the Great Lakes Building & Construction Trades council. Craig F. Walker/Globe Staff

Sandell rattled off a list of plants that had closed: Hammermill Paper, Erie Malleable Iron, and Steris, where his grandfather worked making medical equipment. (The plant announced it would relocate to Mexico in 2006.) The General Electric locomotive factory, meanwhile, has shed more than 1,000 positions since 2013 and is now owned by Wabtec. Residents worried that Erie was no longer a place where a strong work ethic and a high school education were enough to provide for a family.

“Those jobs are gone,” Sandell said. “It’s a hard thing to watch when you lose plant after plant.”

The Erie Malleable Iron Company, on 12th Street, was one of several manufacturing plants to close around Erie. Craig F. Walker/Globe Staff Gallery: Explore Pennsylvania in photos

It was in this environment that Trump rolled into town for a rally in August of 2016. He railed against refugees from Syria — holding up a chart showing their arrival numbers — and promised to build a wall on the Mexican border. Trump also vowed to stop factories from leaving town.

“So Erie has lost a lot, right?” Trump asked. “I promise we can fix it so fast. We will stop these countries from taking our jobs.”

Klinzing was among the 9,000 fans who packed the Erie Insurance Arena that day, delighted to see Trump in the flesh. After quickly growing tired of what he saw as Obama’s overly conciliatory approach to foreign policy, Klinzing appreciated Trump’s tough talk. “What I liked about him is he wanted to take care of America first before all these different countries,” he said.

At the time, Klinzing was worried he might have to leave Erie, where he was born and raised, to find a better paying job. He was waking up at 3 a.m. each day to drive two hours to Reno, Pa. — the closest roofing job he could find that provided the amount of hours he needed. That left less time to spend with his wife, who worked the night shift as a nurse, and his three teenage sons at home.

“We were finding we had to go farther and farther for work,” he said. He was even considering a job offer down in North Carolina, despite not wanting to uproot his family and leave his friends in Erie. “There was a time when I really thought I may go do this,” he said.

Klinzing of McCreary Roofing worked atop a building at the Union City School District. Craig F. Walker/Globe Staff

But it wasn’t just Trump’s promises about jobs that attracted Klinzing, whose arms sport elaborate deer tattoos in homage to his favorite hobby, hunting. He liked the bluster and the bombast, and he related to the way Trump spoke. Klinzing also believed that society had become too politically correct and that minorities play “the race card” and accuse white people of racism too much.

“People look at [Trump] as a bad person, but everyone doesn’t speak proper,” he said. “Look at me, I don’t have that proper language. That’s the way I look at him — he’s just honest.”

Meanwhile, any resistance he received for supporting Trump from those who called his rhetoric racist just put him more firmly in his corner. Klinzing installed a security camera to watch the 20 Trump signs he placed in his front yard after someone tore up the single one he had posted previously and threw it in the street.

Union leaders could sense a larger sea change in the traditionally Democratic area as Election Day loomed in 2016.

“Even my own people who were usually Democrats — they came right out and told me about their vote for Trump,” said John Renwick, a bus driver who is the president of the local transit union. “Boy, we had some heated, heated conversations.”

The president of the union that serves the locomotive plant, Scott Slawson, also noticed a change in the air. “You don’t have to be a genius to figure out when you see a sign for a politician everywhere that chances are that’s the winning candidate,” Slawson said.

Wabtec Corporation, which took over a General Electric plant, is one of the largest employers in Erie. Craig F. Walker/Globe Staff

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In the end, Trump picked off many more union voters than is typical for a Republican presidential candidate, fueling his victory. National exit polling showed Democrat Hillary Clinton won 51 percent of voters in union households, down from the 58 percent Obama carried four years earlier. Union votes in Erie have traditionally been a Democratic stronghold within a Democratic stronghold — but Clinton could barely hold on to a majority of those voters.

“Hillary’s campaign in the last two or three weeks was pretty much, ‘Look how bad he is — you gotta elect me because he’s a jerk,’ ” explained Rick Bloomingdale, president of the AFL-CIO in Pennsylvania. “And Trump’s campaign was, ‘I’m going to bring jobs back.’”

But Bloomingdale — and many other local union leaders who did not follow their rank and file onto the Trump train — believes this election will be different.

“People see that he’s a con man,” he said of Trump. “He made a lot of promises and he didn’t live up to it.”

Coal miners and electricians have been laid off in the state, he said, and a long-promised infrastructure bill never materialized. The manufacturing sector has also shed thousands of jobs in Pennsylvania this year, according to the Bureau of Labor Statistics, and that could affect union workers in factories who were drawn to Trump’s pledge to stop companies from moving plants overseas. Meanwhile, Trump faces an impeachment inquiry, which hasn’t turned off Klinzing but could affect the decisions of other voters.

This brick building once housed the Shaw Piano Company and later the Cohen Industrial Supply Co. in Erie. Craig F. Walker/Globe Staff

But the reality is more complicated. In Erie, the economy has picked up, thanks in part to a wave of construction projects. Two hospitals are building $100 million additions to their complexes, and the largest business in the city — Erie Insurance — is also embarking on an extensive construction project. Two hours south, near Pittsburgh, a giant new plastics factory — called a “cracker plant” because it “cracks” natural gas molecules as it transforms them into plastic pellets — is going up. The $6 billion plant, one of the largest privately funded projects in the state since World War II, is drawing construction workers all the way from Erie.

That construction bonanza could solidify support for Trump among those in building trade unions, like Klinzing, who locals say make up the backbone of Trump’s union fans. Klinzing emphatically credits Trump for the increase in construction jobs. But it’s unclear if his neighbors feel the same way. A September poll from Erie’s Mercyhurst University found that although voters in Erie County feel significantly better about their local economy since Trump took office, a majority of them — 53 percent — still disapprove of the job he’s doing as president. That suggests they don’t credit him with the gains or that other concerns about him outweigh the rosier financial outlook.

Union leaders also don’t see the connection between the construction boom and Trump.

“These types of projects don’t all of a sudden happen because a certain individual in Washington gets elected,” said James Nuber, the business manager of a local electricians union in Erie. “It takes years of planning. But whoever holds the attention of the country can claim responsibility, I guess.”

Trump did just that on a trip to the cracker plant in August, boasting that he gave the workers the project even though the owner, Shell Chemical Appalachia, picked the location in 2012, halfway through Obama’s tenure. (The company credited tax breaks provided by then-Governor Tom Corbett for its decision.)

Casey Richardson sported a roofers union sweatshirt while working with Klinzing. Craig F. Walker/Globe Staff

“This would have never happened without me and us,” Trump proclaimed to an audience of union workers who are building the plant.

The president also delivered a threat to union leaders — who for the most part remain opposed to him — to back him or else.

“I’m going to speak to some of your unions’ leaders to say, ‘I hope you’re going to support Trump.’ OK?” he said. “And if they don’t, vote them the hell out of office because they’re not doing their job.”

Erie’s union leaders point to the comments as one more sign that Trump is no friend to labor and predict he won’t be able to hold onto their votes this time around. But Klinzing said he wasn’t bothered by Trump targeting the union leadership.

“I probably would have laughed and kind of went with it,” he said. “It’s not like he’s out there saying, ‘I’m going to try closing all your unions down.’ ”