Cleveland Cliffs (CLF) and the United Steelworkers union asked a US District Court judge in Pittsburgh on Wednesday to permanently dismiss a lawsuit alleging they conspired to undermine a prospective merger between US Steel (X) and Nippon Steel.

The proposed tie-up was blocked last month on national security grounds by then President Joe Biden following more than a year of opposition led by the Steelworkers union, which argued the deal lacked sufficient safeguards to keep Nippon from eventually shutting down US Steel's production in Pennsylvania and Indiana and moving those jobs to Japan.

Cleveland Cliffs and its Chief Executive Lourenco Gloncalves also opposed the merger proposal, with the mining and steel producer losing out to Nippon with its bid to acquire US Steel late in 2023 and is reportedly now working with Nucor (NUE) to resuscitate the offer, according to a Reuters report.

In calling for the court to dismiss with prejudice four of the nine counts alleged by Nippon and US Steel in their Jan. 6 complaint, the USW and Cleveland Cliffs said the lawsuit was a "frivolous and unsubstantiated attack" on the defendants for exercising their First Amendment rights, according to a statement from the union.

US Steel and Nippon Steel did not immediately respond to a request from MT Newswires seeking comment.

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