North Korea's actions this past week have been thoroughly examined and opined in other places, so I'm not going to go into great depth other than to give a quick recap. They have shot at least (by my count) five missiles of different types, conducted a nuclear test (not definitively confirmed), and threated to back out of the armistice that has been in place since 1953. What has been the general response towards North Korea in all this? 'Come back to the negotiating table'. My response to that suggestion is: or what? There's no reason for North Korea to negotiate right now. There are no consequences for their actions. At this point they can pretty much do what they want and the most they're going to get is hand-wringing. The best illustration I can use as comparison is parents see this with children. Children at one time or another will deliberately disobey the parent as a test. They are trying to see what they can get away with, and for how long. They're also testing the parent: are the rules and boundaries you told me the actual rules? I've seen it multiple times, and the way to shut it down is to look the child in the eye and say 'you sure you want to do that? Okay, but there will be severe consequences', and name them. After that, if the child continues, you follow through. You let the child know they're crossing a line they don't want to cross.
In this case, for North Korea, the consequences cannot be economic sanctions, or similar threat which really won't hurt. Using those methods is essentially telling North Korea 'we really don't mean what we say. But we'd appreciate it if you did what we told you.' There will be no respect from North Korea, and they'll eventually turn into the bully. Making noise and threats whenever they want to get their way. If I were in charge for a day (I know it'll never happen but just let me pretend, okay?), the method I would use with North Korea would probably be something on the lines of 'you want to try to fire a nuclear missile at the US or Japan? Okay, but it will be the last thing you do as a county.' Is that the most diplomatic method? No, I know it isn't. But sometimes diplomacy doesn't work, and you answer a threat with a threat. See who backs down. We've done it before with the Soviet Union and the Cuban Missile Crisis. Will we ever do it again? I don't see the current government doing something like that.