U.S. Steel CEO David Burritt has warned that the company may need to close its mills and relocate its headquarters from Pittsburgh if the $14.9 billion buyout by Nippon Steel does not go through. Burritt emphasized that the nearly $3 billion investment from Nippon is crucial for upgrading aging mills and preserving jobs. The proposed acquisition faces significant opposition from U.S. politicians, including President Biden, Vice President Harris, and Donald Trump, who argue that U.S. Steel should remain American-owned. Nippon Steel has assured that U.S. citizens would hold key management and board positions to address national security concerns. The deal has received some regulatory approvals but is still under review in the U.S.