North Korea has a miniscule economy which means they are printing money to fuel their military. This has never proven to work and just like with Russia and the Cold War, they will experience an economic collapse and will have to build relationships with other countries instead of isolating themselves and waving their fists.
Anyhow, please don't worry too much about North Korea instead worry about China and Japan who own us because of the trillions of dollars of credit Obama received from them to pay for things like Obama Care. They are our masters so beware of the whip.