Funny you should mention Zero’s response (or lack thereof). According to a story I heard during my intel days, we responded to a possible NK threat much differently 20 years ago.
During the run-up to (and execution of) Operation Desert Storm, there was concern that the Norks would use the opportunity to roll south. Back in those days, we supposedly had the capability to fight to MRCs simultaneously, but it would have been tough.
Just to let the DPRK know where we stood, the U.S. asked the country that represents us in Pyongyang (Sweden, I believe) to set up a meeting between a senior U.S. official and his North Korean counterpart. One version I heard said the meeting occurred at a Swedish embassy in another Asian country; other accounts suggest it too place in Europe.
The session began with the DPRK emissary delivering his ususal propaganda blast. The U.S. official just sat there and let him finish. The American’s response was simple and direct: “as you know, we are currently engaged in the Persian Gulf region. You should not interpret this as a sign of weakness or our inability to respond to threats in Northeast Asia. If you make that mistake, you will suffer the consequences.
With that, the American official shoved a small map across the desk, depicting all of the cities, military bases and other facilities that would be targeted in a full-scale nuclear laydown on the DPRK. I was told there were literally hundreds of red target triangles on the map. The graphic showed that we were prepared to hit them with everything, from ICBMs and SLBMs, to tactical nukes.
With that the meeting ended. And North Korea was as quiet as a mouse during the first Gulf war.
I’ve heard that account before too.