President Joe Biden decided to block the $14 billion takeover of US Steel by Japan’s Nippon Steel even though some top US officials did not believe there were sufficient national security grounds to kill the deal,

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.

The pushback comes after US Steel Chief Executive Officer David Burritt on Friday condemned Biden’s order, calling it a “shameful and corrupt” move that harmed the company and America’s steelworkers and “insulted” US ally Japan.