Environmentalists are hailing the White House’s recent order to block Nippon Steel from buying US Steel, saying a takeover by the Japanese giant would have guaranteed many more years of carbon-intensive,

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.

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.