N. Korea possibly thinking of invading S. Korea?

North Korea Forum

Why all the sudden does N. Korea want to restart it's nuclear program and end the armistice that halted the Korea War?

It's logical to think that the North wants to be a nuclear power so once it invades S. Korea, it can threaten the U.S. with nuclear weapons if the U.S. intervenes. It probably wants to reunite both Koreas.