WW3 will not start with north korea. They send 1 or 2 missiles at us and we will vaporize 98% of their entire population 10 minutes later. The other 2% will then become our slaves.
With Obama as president, the US will probably just lodge a protest with the United Nations and beg N. Korea for forgiveness for whatever we've done to make them mad at us.
Latest estimates we still got three more years for that to happen. Something tell me the S$&t going to hit the fan when they fire the practice missile at Hawaii.
North Korea can barely find the keys to their equipment. They haven't had a successful launch yet, by modern standards of success. They have nothing but a large ground force.