Harris will make the remarks at a Labor Day event with unions in Pittsburgh, home to both U.S. Steel and the United Steelworkers union, which opposes the sale, an official familiar with her plans said. Harris will emphasize a commitment to supporting American steelworkers, the official said.

The statement is her first on the proposed deal and echoes President Joe Biden’s stance, which has stopped short of blocking the deal entirely while a security review is underway. GOP candidate and former President Donald Trump has also called for blocking the transaction.

It’s unclear whether a decision on the acquisition will land on Biden’s desk or that of his successor — or even whether it will go through at all. Still, Harris’ comments add to the political maelstrom surrounding the $14.1 billion deal — rooted in Pennsylvania, one of the election’s key battlegrounds. The state’s two senators have been among the most vocal opponents of the sale, as has Sen. J.D. Vance of neighboring Ohio, who is Trump’s running mate.

Read more: Japanese US steel takeover creates storm in election year

Nippon Steel announced last week that it will invest an additional $1.3 billion in US Steel’s unionized factories, hoping to convince the union that it has raised concerns about the long-term prospects for workers once the current labor agreement expires in 2026.

‘Unwavering dedication’

In response to reports of Harris’ planned campaign announcement, US Steel emphasized that commitment and that it still stands by the deal.

Nippon Steel’s pledge to invest is “evidence of its unwavering commitment to U.S. Steel and all of our stakeholders” not only to complete the transaction but also to protect and grow the business, Chief Executive Officer David Burritt said in a written statement Monday. “U.S. Steel will be a much stronger company as a result of the transaction and these investments.”

Shares of U.S. Steel rose when Nippon’s bid was announced in December, before giving up much of those gains as Trump and Biden came out against the offer. The stock then outperformed peers after Biden dropped out of the race on bets that a Harris-led ticket would pose fewer obstacles to getting the deal done. Trading was closed Monday for a U.S. holiday.

Read more: Nippon Steel steps up efforts to woo U.S. steelworkers, politicians

Debate over the takeover has intensified in the run-up to the November vote, though there is little sign that the deal will be finalized before then. It remains under review by the Committee on Foreign Investment in the United States, a panel chaired by the Treasury secretary that has frequently targeted U.S. adversaries such as China. The Biden administration has so far deferred to that ongoing review.

Harris visits Michigan on Monday for a Labor Day event before traveling with Biden to Pittsburgh — their first joint campaign event since she was nominated. They will attend an event at a union hall with leaders of many of the country’s leading labor groups, including the United Steelworkers.