your first problem is you're assuming present relations would stand
if we dropped 10 fukking nukes on NK everything goes out the door
to say japan wouldn't make the slightest move against us
maybe they do, maybe they don't, but you don't know. historically speaking it's safe to assume nuclear weapons would make the japanese nervous.
the insanity of the US dropping 10 nukes on a territory might cause the US to lose ALL allies and shake up ALL present global geopolitical alliances
there really is no logical way to answer this question
edit: not to mention the nuclear fall out and radiation poisoning that would plague south asia for the next 2 generations.
the most realistic outcome is a 30 year reset button is pushed on society.
hope yall ready for the resurgence of disco