The US can not rule out that the North Koreans will fire the very first nuclear tipped ICBM they produce towards Washington DC. So, the US must and will plan for the contingency. Nobody understands North Korea sufficiently to rule a strike out. It may seem mad and inhumane but anyone who has following NK over the last decades knows full well the regime there is mad and inhumane. For those that don’t, a scan of e.g. Amnesty International’s records on the country ought to be convincing enough.
Does China know that the US must plan to protect itself? This really is about China and its mad wild card North Korea. It does seem that China has the economic muscle to bring the North Korean economy to its knees and change the regime; The alternative is having the US under an unpredictable damoclean sword. What will China choose? So far the choice is to ignore the problem.
The solution here is to put pressure on China, that its position is untenable and that if it doesn’t start playing a globally responsible role, sanctions that target NK could be extended to anyone who does business with NK. If a bank or company wants to do business with NK then it won’t be able to do business with the US, Europe and others endorsing such a sanction. Such a sanction regime would force China to make a choice, forcing it away from deadly poker towards responsibility.
Someone told me recently it may be impossible to prevent NK and Iran from becoming nuclear powers, but it may not be as impossible to prepare an international stance solid enough to deter them from ever using those powers. I tried to find a way to disagree because inherent in having nuclear weapons is carte blance to execute ones agenda short of nuclear war. And that there simply wasn’t sufficient international coherence to signal deterrence. But I couldn’t disagree with that the likelihood that NK and Iran develop nuclear weapons is far larger than the likelihood that the ‘international community’ can do anything about it.