When President Biden told a crowd of union workers this year that every American should have a path to a good career — “whether they go to college or not” — Tyler Wissman was listening.

A father of one with a high school education, Mr. Wissman said he rarely heard politicians say that people should be able to get ahead without a college degree.

“In my 31 years, it was always, ‘You gotta go to college if you want a job,’” said Mr. Wissman, who is training as an apprentice at the Finishing Trades Institute in Philadelphia, where the president spoke in March.

As Mr. Biden campaigns for re-election, he is trying to bridge an educational divide that is reshaping the American political landscape. Even though both political parties portray education as crucial for advancement and opportunity, college-educated voters are now more likely to identify as Democrats, while those without college degrees are more likely to support Republicans.

That increasingly clear split has enormous implications for Mr. Biden as he tries to expand the coalition of voters that sent him to the White House in the first place. In 2020, Mr. Biden won 61 percent of college graduates, but only 45 percent of voters without a four-year college degree — and just 33 percent of white voters without a four-year degree.

“The Democratic Party has become a cosmopolitan, college-educated party even though it’s a party that considers itself a party of working people,” said David Axelrod, a top adviser to former President Barack Obama.

Mr. Axelrod added that the perception that Wall Street had been bailed out during the 2008 recession while the middle class was left to struggle deepened the fissure between Democrats and blue-collar workers who did not attend college.

The election of Donald J. Trump, who harnessed many of those grievances for political gain, solidified the trend.

“There’s a sense among working-class voters, and not just white working-class voters, that the party doesn’t relate to them or looks down on people who work with their hands or work with their backs or do things that don’t require college education,” Mr. Axelrod said.

Now, in speeches around the country, Mr. Biden rarely speaks about his signature piece of legislation, a $1 trillion infrastructure bill, without also emphasizing that it will lead to trade apprenticeships and, ultimately, union jobs.

“Let’s offer every American a path to a good career whether they go to college or not, like the path you started here,” Mr. Biden said at the trades institute, referring to its apprenticeship program.

The White House says apprenticeship programs, which typically combine some classroom learning with paid on-the-job experience, are crucial to overcoming a tight labor market and ensuring that there is a sufficient work force to turn the president’s sprawling spending plan into roads, bridges and electric vehicle chargers.

Mr. Biden has offered incentives for creating apprenticeships, with hundreds of millions of dollars in federal grants for states that expand such programs.

“Biden is the first president that’s reducing the need to get a college degree since World War II,” said Douglas Brinkley, a presidential historian.

Mr. Biden’s approach is a shift from previous Democratic administrations, which were far more focused on college as a path to higher pay and advancement. Mr. Obama, during his first joint session of Congress, said that the United States should “once again have the highest proportion of college graduates in the world.”

Mr. Obama’s wife, Michelle Obama, started a campaign encouraging Americans to go to college, at one point suggesting in a satirical video that life without higher education was akin to watching painting dry.

Democrats have long walked a careful line on the issue. Mr. Biden has been a champion of higher education, particularly community colleges, and one of his most ambitious proposals as president was a $400 billion program to forgive student loan debt for 40 million Americans. Republicans have portrayed that proposal as a giveaway for elites.

Mitch Landrieu, the president’s infrastructure coordinator, said Mr. Biden had always believed college was important, but “it is absolutely not the only way to build an economy.”

“He sees that men and women like that have been left behind for a long time,” Mr. Landrieu said of people without college degrees. “They’ve always been part of the Democratic Party. It’s not until recently that’s changed.”

The shift coincides with a stark political reality.

The battleground states that voted for the winning candidate in both 2016 and 2020 rank roughly in the middle on higher-education levels, which means that Mr. Biden’s effort to appeal to those without a degree could make a real difference in 2024, according to Doug Sosnik, a former senior adviser to President Bill Clinton.

“You need to both try to mitigate losses with noncollege voters and at the same time try to exploit the advantage in those states with educated voters,” Mr. Sosnik said. “You can’t rely on the diploma divide solely to win. But it’s part of the formula.”

A similar dynamic is playing out nationwide.

Gov. Josh Shapiro, Democrat of Pennsylvania, released campaign ads focused on expanding apprenticeships and removing requirements for college degrees for thousands of state government jobs — a pledge he made good on when he entered office. Republicans in Maryland, Alaska and Utah have removed similar degree requirements.

Gov. Spencer Cox, Republican of Utah, said he was not only hoping to address a stigma attached to those who do not attend college but also appease employers increasingly anxious about persistent worker shortages.

“We can’t do any of this stuff if we don’t have a labor force,” Mr. Cox said.

Christopher Montague, 29, an Air Force veteran from the Philadelphia suburbs, who trained as an apprentice in drywall instead of going to college, said he had noticed an “awakening” by politicians on the upside of pursuing training in trades.

“There is money in working with your hands,” he said.

At the Finishing Trades Institute in Philadelphia, instructors say they have noticed an increase in demand. Drew Heverly, an industrial painting instructor, said he typically had 10 apprentices working on construction projects in “a good year.”

This year, he has already sent nearly 40 apprentices to work on projects in Philadelphia that are partially funded by Mr. Biden’s infrastructure package.

“We’ve definitely see the ramp-up and the need for manpower,” Mr. Heverly said.

The prospect of pursuing an education in trade while earning money on projects has also gained momentum among high school students, according to the Finishing Trades Institute’s recruitment coordinator, Tureka Dixon. Community colleges in the area are even reaching out to see if they can form joint partnerships to train students on trade.

“Whether it’s cranes, high-rise buildings, bridges, that is trade work,” Ms. Dixon said as the apprentices in hard hats listened to a lesson on lead removals. “That is physical labor. That is the country, so I think people need to consider it more.”

Mark Smith, 30, who is training as an apprentice at the institute, said learning a trade was not a fallback position for him — it was his preferred career.

“School wasn’t for me,” Mr. Smith said. “I did the Marine Corps and then I started right in this. For me it was a waste of money.”

Mr. Wissman, who has never voted in a presidential election and identifies as an independent, said he was not sure yet if the recognition from the White House would move him to finally vote in the 2024 election.

“I want in office whoever is going to help me put food on my table,” said Mr. Wissman, whose girlfriend is pregnant with their second child. “At the end of the day, that’s all it’s going to come down to.”