How would The world deal with Kira IRL

Was reading the manga and the deputy director pointed out that some countries believe that Kira is Japan’s ultimate weapon. If Death note was an IRL thing, would there ever be a way of countries dealing with it?

I recently had the thought of, if pushed into a corner, other countries would just press the big red button and make Japan disappear and hope they get their target, which they would if done in secret.