U.S. President Joe Biden’s decision to reject a bid by Nippon Steel to acquire U.S. Steel on national security grounds isn’t the first time friction over trade and investment has irked Washington’s closest ally in Asia.

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.

US Steel and Nippon, whose $14.3 billion merger was blocked by President Joe Biden last week, filed a lawsuit against the US government Monday, claiming Biden’s executive order to bar the companies from combining was signed for “purely political reasons.