The big deal about North Korea is pretty simple but very complex in terms of what can happen. First, North Korea is not part of any treaty and there are no IAEA or NSG safeguards in what they are doing. It’s pretty evident North Korea’s intention is to threaten the US mainland directly - in their own words and refuse to participate in talks. They are heavily sanctioned by the world community by way of the UN Security Council. They have also threatened “pre-emptive” nuclear strikes to the US. Even though North Korea would like to portray that being a nuclear power is necessary to ensure the survival of their regime while at the UN (using Iraq and Libya as examples), they may want to go back to the Cuban Missle crisis to understand how Americans react in those circumstances.
North Korea has always had a deterrent with armaments pointed directly toward Seoul and this has survived the regime for decades. So, the logic in a duplicative deterrent-only capability with more destructive power is suspect particularly under threat of a pre-emptive nuclear strike on the US mainland.
In my opinion, it comes down to this: There is a grave danger for a miss-calculation on the part of the North Korea regime. The prospect of shooting a missile toward Guam and land it 20nm offshore as a show of strength (as they advertised they are aiming for with their ICBM program…no pun intended) will certainly invite a response from the US. And, they will get it.
The problem with any response from the US is the method in which this would happen. It’s very problematic. The only way the US can defeat, defend and be effective against this regime in a strike is by using tactical nukes (variable/dial-a-yield) in parallel to other surgical strikes. That is the only way to decapitate the regime fast enough to protect South Korea. The US does not want this, nobody does. But, we do have the capability and General Mattis said it best today, “we are not looking to annihilate an entire country”. Unfortunately, to win, you are looking at just that in no uncertain terms and General Mattis knows this. This is not worth it and unimaginable. Will most Americans bear the brunt and suspend all trade with anyone dealing with North Korea? This is pretty much one of the last diplomatic steps. These steps will not work as far as North Korea giving up Nuclear Weapons, however. It has been estimated that without fuel, the regime is good for about a year, maybe longer since all will be directed to the military. Cut that off, and wait them out…even if it takes 3 years. I doubt very seriously that China will trade oil exports to North Korea for $600 Billion / year in exports to the US. The trick will be finding the solution without the perception of China falling to US pressure.
So, that is the big deal to me and a big one at that.