President Biden blocked Japan's Nippon Steel from buying U.S. Steel last week, earning the approval of the United Steelworkers union, which desperately wanted the deal crushed. But steel workers themselves may be less than enthused.

The suit, filed in the U.S. Court of Appeals for the District of Columbia, alleges that it was a political decision and violated the companies’ due process.

U.S. Steel and Japan’s Nippon Steel sued the United States government on Monday in a last-ditch attempt to revive their attempted merger after President Biden blocked it last week on the basis that the transaction posed a threat to national security.