And it's wrong for national security.

Is it?

U.S. Steel isn't the largest steelmaker in the U.S. any more. It might not even be the number two steelmaker. It appears that X produces just under 20% of annual steel output in the U.S. Which isn't nothing, but it also means having ownership by Japan might not necessarily present any real national security issues.

AIUI, X has been the industry laggard for a while as well - with declining production over time. So the flip side to the risks of foreign ownership of the company is any possible benefit to increased production from domestic sources rather than relying so much on imported steel.

I suppose that will all come out in a lot of analysis. I don't know the answer, since there's so many different types of steel and the military has very specific needs. But I don't know that it's cut and dried.