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

President Joe Biden decided to block the $14 billion takeover of US Steel by Japan’s Nippon Steel even though some top US officials did not believe there were sufficient national security grounds to kill the deal,

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