Strong Support Here Helped Trump Win Pennsylvania in 2016. 2020 Could Be Different.

ALTOONA, Pa. — President Trump’s road to re-election runs through places like Altoona, with its deep working-class roots, conservative social values and nearly all-white population. But it is not a straight line.

He won about 70 percent of the vote in Blair County, where Altoona is the largest city, in 2016, and that support was an integral part of why Mr. Trump defied forecasts and carried Pennsylvania, a state that will again be critical to his chances in 2020, by about 44,000 votes.

Altoona’s voters have now had more than two years to assess whether Mr. Trump has honored his campaign commitments and whether they will support him again so enthusiastically. Their answer, judging from interviews with more than two dozen voters, is complicated, not the black and white narrative that either Mr. Trump’s supporters or his critics might assume.

Most of his supporters say they will stick with him, citing his blunt style, which some of them see as a form of entertainment, as well as a strong economy. But not all of them.

That same economy has yielded uneven results in Altoona, a city of about 45,000 where the low unemployment rate of 4.2 percent masks some uglier economic facts: Most of the new jobs are in lower-paying service industries, with scaled-down benefits. The poverty rate is 23.2 percent. And there are few signs of the renaissance in manufacturing that the president said he would create.

“There is not a lot of disposable income at $11 an hour,” said Jim Foreman, the county Republican chairman, who operates several physical therapy clinics.

Robert K. Kutz, the president of a local labor council, put it more bluntly. He said some union members who voted for Mr. Trump were starting “to realize that the promises came up empty” and will vote against him in 2020.

“As far as the manufacturing goes,” he added, “none of that has come back.”

Mr. Foreman also acknowledged that it would be difficult for Mr. Trump to replicate his overwhelming numbers from 2016. And if the numbers fall off in rural counties like his, Mr. Trump’s path to winning a state where Democrats picked up three House seats in the midterm elections becomes more challenging.

Val DiGiorgio, the Republican state chairman, said the challenge would be to maintain Mr. Trump’s margins in rural areas while trying to blunt an expected surge of Democratic voters in suburban areas of Philadelphia and Pittsburgh. “That’s the question,” he said.

But there are few signs that Republicans have lost their hold in Altoona. The area is represented by Representative John Joyce, a dermatologist elected for the first time in November with more than 70 percent of the vote. The district is largely Catholic and fervently anti-abortion, helping Mr. Trump.

And there are Trump supporters like Sarah Vogel, who said she wanted to live in her hometown to help its revitalization efforts and opened a coffee shop downtown. “He’s doing what he can to help small businesses and rural areas,” she said. “I don’t know if I can give any specifics.”

But, she said, she is “personally a little bit torn” over Mr. Trump’s hard-line immigration policies. While she voted for him in 2016, she is waiting to see who the Democrats nominate before making up her mind this time. Her strong opposition to abortion will weigh heavily in her decision, she added.

Cultural issues could outweigh economic interests for many voters.

Over lunch with his mother at the Black Dog restaurant near Altoona, Dr. Levi Delozier, a Democrat who returned home to practice medicine, said those issues motivated many voters here in 2016.

“I think cultural beliefs and social mores pervade every decision they make,” Dr. Delozier said. “The haze and the fog and the ether of the campaign made people feel like they were better off. I think the current president is very astute at programming his quote-unquote wins, and he is very good at off-loading losses.”

Altoona includes ancestral Democrats, voters whose family members worked for the railroad or a coal mine, but increasingly have supported Republicans. Older voters in particular, and especially those who had manufacturing jobs, believe that Washington has become out of touch, and are more likely to be Trump supporters.

Gib Beckwith worked in manufacturing much of his life. He lost his job as a tool and die maker, but sought retraining and now has an information technology job at North American Communications, which produces envelopes for direct mail.

Mr. Beckwith gets his news from Fox. “I know it is biased, but I get more truth out of their news than anyone else,” he said. “And it’s on my radio. On the weekends, it’s on. I won’t watch NBC or CBS anymore.” He said no one in his family, “not a one,” will vote for anyone other than Mr. Trump.

“Did he do better for the working man? Most certainly,” Mr. Beckwith said. “He has brought what jobs he could bring back, and yes, he gave the rich a tax break, but I got a tax break as well.”

Views like his present a studied contrast to a generation ago, when the federal government delivered big for people here. A former congressman, Bud Shuster, who was chairman of the House Transportation Committee, was famous for securing projects for the area, most notably the extension of Interstate 99, which some have mocked as “the road to nowhere.”

Mr. Shuster was so successful securing federal largess that when reporters asked Senator Daniel Patrick Moynihan of New York which state received the most funding one year, he replied, “The state of Altoona.”

But congressional earmarks are now banned and Mr. Shuster’s political career is long over, his politics of accommodation and compromise replaced by stark polarization.

North American has been churning out envelopes for direct mail solicitations for 40 years, and a sign outside its sandy brick headquarters says “Now Hiring,” proclaiming what should be good news for both the city and Mr. Trump.

Not so long ago, the company transferred most of its production jobs to Mexico, taking advantage of lower-cost labor. Then came Mr. Trump’s hard-line immigration policies and with them increased chaos that led many customers to say they no longer felt comfortable with their time-sensitive mailings subject to disruption.

So the company is trying to “reshore” several hundred light manufacturing jobs back to Altoona, just the kind of thing the president promised to do as the champion of the “forgotten American.” But company officials said Mr. Trump’s approach includes almost nothing that would assist them in bringing back jobs.

“There is no federal program to help businesses like ours to reshore our jobs,” said Tera Herman, the company vice president.

Her husband, Robert Herman, the company president, lived in El Paso for a time when the company had operations in Ciudad Juárez, Mexico. He said he did not like the way the Trump administration’s immigration policies had played out.

“I am a registered Republican,” Mr. Herman added. “I like Republican ideals on the economy. But I don’t like the way that it’s translated. It seems very at times bigoted and the language that’s used, the derogatory references. I am not that way.”

Workers at Mr. Herman’s company reflected similarly conflicting sentiments about the president. Cory Reed is the third generation in his family to work at the facility in Altoona. He voted for Mr. Trump in 2016, but doubts he will again.

“He hasn’t really fulfilled that promise,” Mr. Reed said of the president’s ode to the forgotten American. “The follow-through wasn’t there.” He is also fed up with the president’s tone. “I feel like there should be more important issues than someone completely bashing someone on Twitter. I don’t really agree with that at all.”

But like Mr. Beckwith, Rick Zupon remains solidly behind Mr. Trump.

In Mr. Zupon, a lifelong Altoona resident who twice voted for President Barack Obama, Mr. Trump has an unwavering convert. “The guy has all the money in the world but is still looking out for the guy who made the country what it is,” he said.

Mr. Trump was the plain-spoken truth teller Mr. Zupon wanted to see shake up Washington. “Another thing I like about President Trump: He doesn’t use language that you have to get a dictionary to understand,” he said. “That’s kind of enjoyable coming from a president of the United States.”

John Stultz, a local real estate agent, also finds Mr. Trump entertaining. Some nights he says to his wife, “I’m going home to watch the national news tonight to see what he said.”

But, he added, he would consider a candidate like former Vice President Joseph R. Biden Jr. “I like Joe,” he said, “even the touchy-feely.”

For the president, voters like Mr. Stultz make Pennsylvania particularly challenging, especially if Mr. Biden, who was born in the state and plans to make the first speech of the presidential campaign he is expected to launch on Thursday in Pittsburgh, becomes the Democratic nominee.

Some in the Democratic Party say its nominee should focus on the so-called Obama coalition of younger voters, minorities and suburbanites. But Democrats like Mr. Biden have said the party should not abandon rural voters and should lay its own claim to the “forgotten American.”

In 2016, in Blair County, Hillary Clinton ran seven percentage points behind Mr. Obama’s performance in 2012. If a Democrat can simply cut into Mr. Trump’s numbers here, much less match Mr. Obama’s, Mr. Trump’s Pennsylvania victory could seem more aberration than trend.