Biden to block Nippon's acquisition of U.S. Steel, reports say

Zoom in: Biden's move to block the deal, expected in the next few days, will be based on national security grounds, the Financial Times reports. The Washington Post was first to report Biden's intentions Wednesday afternoon.

The intrigue: CFIUS, the Committee on Foreign Investment in the United States, has been investigating the deal's impact on national security.

• Japan is a key U.S. ally, not the kind of threat that CFIUS typically guards against.
• But the Nippon deal has apparently drawn concerns. The FT reports that the committee has already told Nippon that such threats could not be overcome.

What they're saying: "CFIUS hasn't transmitted a recommendation to the President, and that's the next step in this process," a White House official tells Axios.

Meanwhile, efforts to push this deal through have only intensified since Monday when Kamala Harris said U.S. Steel "should remain American-owned and American operated."

• Previously, Donald Trump said he'd stop the deal if elected, though as Axios' Dan Primack notes, it's scheduled to close prior to inauguration day.
• But both Nippon and U.S. Steel are wielding sticks and carrots to make this happen in spite of the politics.

U.S. Steel earlier Wednesday warned in a statement that without the deal, the company will close plants and move its headquarters out of state. It would put "thousands of good-paying jobs at risk."

• Nippon, meanwhile, has announced that it would invest billions above the deal terms in the company.
• And on Wednesday, it announced more sweeteners, pledging in a release that U.S. citizens would make up the majority of the newly formed U.S. Steel's board post-acquisition.

The stepped up efforts led to a bizarre "rally" of U.S. Steel workers in Pittsburgh this afternoon, gathered by the company outside its headquarters to show support for the beleaguered deal.

• But this wasn't a union thing. The Steelworkers called out the company's moves late Wednesday morning.
• "Today's pathetic attempt to orchestrate a rally in downtown Pittsburgh shows that U.S. Steel is becoming increasingly desperate to save the deal," United Steelworkers president David McCall said in a press release.

What they're saying: It's not so unusual for a company to use workers to political ends at rallies or other events, says John Logan, a labor historian at San Francisco State University.

• Back in 2012, workers at an Ohio coal mind told reporters that they showed up at a rally for Republican presidential hopeful Mitt Romney when asked by management, for fear of losing their jobs.

What's next: Timing on Biden's announcement is unclear. Harris will be in Pittsburgh Thursday for a rally.

• After that, any effort to block the deal could end up in litigation. U.S. Steel shares are tumbled on the news, closing down over 17% Wednesday.

This report updates U.S. Steel's stock price movement Wednesday.