The U.S. decided to take North Korea off its official list of "terrorism-sponsoring" countries as a way of defusing the situation and perhaps punting the problem to the next president. As this Register editorial explains, that delisting was the North's condition for disassembling (or perhaps pretending to disassemble) its nuclear weapons program. It would hardly do to trust Pyongyang, but at least the next president will be faced with a problem there, not a burgeoning crisis.
I still think that the Hermit Kingdom is trying to come out of its isolation and sees threats and nuclear programs as the only way to get U.S. attention. Anne Applebaum over at Slate sees things in a much less sanguinary light.