Trump opposes U.S. Steel's sale to Nippon, but CEO David Burritt believes he can convince the president-elect that the deal is in the interest of U.S. workers.

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.

President-elect Trump has also opposed Nippon Steel's $15 billion acquisition of U.S. Steel, which President Biden blocked last week.

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.

Even if losing domestic sources of primary steel does not seem like a national security threat today, it might tomorrow.

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 president said he was moving to protect national security in deciding the fate of the iconic Pennsylvania-based company, which became a contentious political issue in an election year.

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.

President-elect Trump on Monday accused President Biden of making the presidential transition difficult, citing recent executive orders on climate and other official acts Biden has taken in his last weeks as president.

Japan's Nippon Steel and Pennsylvania-based U.S. Steel are suing the U.S. government for stopping Nippon's nearly US$15 billion purchase of U.S. Steel. U.S. President Joe Biden blocked the deal, citing national security concerns and fulfilling a campaign promise.

Japan's Nippon Steel agreed to buy U.S. Steel. The companies accused the President of trying to gain support from the United Steelworkers union.