Blocking Nippon Steel from acquiring U.S. Steel lays the groundwork for a major consolidation of American steelmaking that will harm consumers and the economy.

U.S. Steel and Nippon Steel said on Monday that it is suing over President Joe Biden's decision to block its sales agreement and a domestic competitor and union over their actions to scuttle the deal.

The companies argued in a lawsuit announced on Monday that Biden violated the Constitution by blocking the merger via a sham national security review that deprived the companies of their right to a fair process.