The missle launches are complete propaganda. Not only is it unlikly that North Korea would start a war, but if a war started they probably would never use them. Not only are they not relible, but they are not effeicent. North Korea has a number submarines that fire topedos that can have nulcear warheads. With these they could destory large parts of the Japanese coastal Cities, and although Japan has a fair navy with good ASW, with enough time and planning the North Korea will fined a way to get by it.
The US also keeps improving anti-missle weaponry every few years and as long as the US keeps its R&D funding it will have defences that can completly shield our allies and certainly any of our cities. I am not worried at all about nukes being fired at the United States and i dont see why anyone esle should be.
In my opinion this whole North Korean nukes issue will defuse when either, Kims son becomes in charge in which case he might not be as insane as his father and instead open North Korean up to the rest of the world, the Military leaders or whatever other political leaders in North Korea get sick of the mismangement and have a coup putting them in charge and then ending the nuke porgram and again opening the country to the rest of the world, or the Chinese might have support a coup inside that country so they can control what happens.