Unfortunately, North Korea is getting better at creative aggression. It paid no real price for sinking a South Korea naval corvette in 2010, killing 46 sailors. It was not deterred after its cyberattack on Sony Pictures last year (which probably put a permanent end to Hollywood lampooning the regime).
Furthermore, amid failed policies by the last three U.S. administrations, North Korea has evolved from a basket case devastated by famine in the mid-1990s to an apparently stable power that soon will hold a nuclear Sword of Damocles over its opponents. And Pyongyang also excels at proliferation — it helped Syria build a plutonium-producing nuclear reactor and is accused of aiding Iran with its ballistic missile program.
In sum, North Korea is actually becoming a bigger problem. It is adept at harming the free world but stopping just short of actions that would draw serious retaliation. And it has an overconfident dictator who benefits personally from aggression, as it enhances his position with North Korea’s military.