U.S. Steel and Japan-based Nippon Steel sued the Biden administration on Monday over a decision made last week to block a merger between the two companies. A proposed acquisition of the second-largest domestic steel producer by Nippon for nearly $15 billion would threaten U.S. national security, the Biden administration said.

The lawsuit, filed in a federal court in Washington, accused Biden and senior administration officials of corrupting the deal’s review process, and harming American steel workers by blocking the