North Korea continues to engage in missile launches. So much for being intimidated by words. Do we declare war before or after people die?

I find it interesting that the PM of Japan has suddenly come to the conclusion that N Korean missiles pose a serious and grave threat. I guess he had to start dodging them for it to be taken seriously. We in the USA do not declare war, whether people die or not. We're great at preemptive strikes and police actions, but we never declare wars nor fight them to total victory. The idea is to spend blood and treasure without gaining the upper hand or successfully meeting military objectives.