North Korea has threatened to use nuclear weapons if attacked.
Okay, so don't attack them.
However, the minute North Korea launches any attack on its neighbors should be the trigger to obliterate their entire military and government.
ALL OF IT.
What's left of the country gets reunited with the South. The remaining people of North Korea will be infinitely better off. And the United States can close up the bases we've been manning at rather high cost for the past 50 years.