PITTSBURGH >> Generations of Pittsburghers have worked at steel mills, rooted for the Steelers or ridden the rollercoaster at Kennywood amusement park, giving them a bird’s eye view of the massive Edgar Thomson Works, the region’s last blast furnace.

Now, Steeltown USA’s most storied steel company, U.S. Steel, is on the cusp of being bought by Japanese steelmaker Nippon Steel Corp. in a deal that’s kicking up an election year political maelstrom across America’s industrial heartland.

The sale comes during a tide of renewed political support for rebuilding America’s manufacturing sector and in the middle of a presidential campaign in which the politically dynamic Pittsburgh region is a destination for President Joe Biden, former President Donald Trump and their surrogates.

The deal follows a long stretch of protectionist U.S. tariffs that analysts say has helped reinvigorate domestic steel. And it is eliciting complicated feelings in a region where steel is largely a thing of the past after people, particularly those 50 or older, watched mills shut down and their Rust Belt towns wither.

“The fear is that these jobs went away once, and the fear is that these jobs could go away again,” said Mike Mikus, a Pittsburgh-based Democratic campaign consultant whose grandfather lost his steel mill job 40 years ago.

U.S. Steel is no longer a major steelmaker in an industry dominated by the Chinese.

But its workers still carry political heft in what some see as a larger symbolic fight to save what’s left of manufacturing in the United States.

With the United Steelworkers against the deal, Biden — a Democrat who has made his support for organized labor explicit and has won the union’s endorsement — has all but vowed to block U.S. Steel’s sale, saying in an April rally with steelworkers in Pittsburgh that the company “should remain totally American.”

Trump, a Republican who as president opposed union organizing efforts but describes himself as pro-worker, has said he would block it “instantaneously.”

Biden’s White House has indicated the secretive Committee on Foreign Investment in the United States will review the transaction for national security concerns. The committee can recommend that the president block a transaction, and federal law gives the president that power.

In the meantime, the Department of Justice is reviewing it for antitrust compliance, and the steelworkers union has filed a grievance over it.

In a rare flurry of bipartisan unity, the sale has drawn opposition from Democratic Sens. Bob Casey and John Fetterman of Pennsylvania and Sherrod Brown of Ohio and from Republican Sens. J.D. Vance of Ohio, Ted Cruz of Texas and Josh Hawley of Missouri, on both economic and national security grounds.

Nippon Steel has scheduled the deal to close later this year.

Once the world’s largest corporation, U.S. Steel was the world’s 27th-largest steelmaker in 2023, according to World Steel Association figures. It reported just under $900 million in net income on $16 billion in sales last year.

The deal includes all of U.S. Steel’s ore mining, coking, steelmaking and processing plants around the country, including the Edgar Thomson Works, which looms over the Monongahela River just south of Pittsburgh and still churns out steel slabs 150 years after it was built.

U.S. Steel employs 3,000 people at its four major Pennsylvania plants, including the Edgar Thomson and the nation’s largest coke-making plant in nearby Clairton.

Nippon Steel — the world’s fourth-largest steelmaker in 2023, according to association figures — and U.S. Steel are now in the midst of a broad public relations effort to promote the sale.

Their ads are on social media, TV screens and billboards, as the companies promise to protect jobs, move Nippon Steel’s U.S. headquarters to Pittsburgh from Houston and invest in the badly aging Pittsburgh-area plants to make them cleaner and more efficient.

Flyers landing in Pittsburgh-area mailboxes tout the “future of American steel” and urge residents to contact their elected officials to support the companies’ “partnership.”

And, they say, “U.S. Steel remains U.S. Steel.”

Meanwhile, Pittsburgh is a changed place.

It is no longer a destination for new steel investment. Gone are the 20 or so miles (32 kilometers) of contiguous iron and steel mills from downtown Pittsburgh and up the Monongahela River that helped the U.S. industrialize and wage wars.

Now, Pittsburgh is seen as an “eds and meds” city in which universities and hospitals are the major employers.

Allegheny County, which surrounds Pittsburgh, just began growing again, after decades of population decline. Some city neighborhoods have emerged from a long period of struggle and are thriving, and a younger generation is attracted to the city’s growing high-tech industry.