It really doesn't make any sense to me that blaming North Korea serves a political agenda for the administration. They have a limited time left in office and they're trying to use it to accomplish something in foreign policy (so far, Cuba, a climate deal with China). This is particularly important since the President's domestic influence will be limited. This business with North Korea seems like a distraction. It's not serious enough that it's going to change anything in the relationship between the US and the DPRK. The DPRK is so unpredictable that starting a beef with them unnecessarily seems like a terrible idea. It's another item on the agenda with China, and I'm sure that there are a lot of other things that we would rather be discussing with the Chinese.