What if we've already got missiles far more advanced than they could come up with in 10 years? We would be keeping ahead of them for a while, and during this time they can spend that money to better the economy.

For me it isn't so much that we have better missiles, it is the missile defense network and such things. Some nations 'play fair' and won't attack us for fear of our attack. The N. Korea leader has demonstrated a 'in your face' & 'I don't care what anyone thinks' attitude. They could do us a lot of damage with one of their low-tech missiles, if we don't have an effective 'missile interceptor' program up and running.

Also, I wonder how much N. Korea is merely a 'pawn' used & subversively encouraged by larger powers to do things that they won't due for fear of 'looking bad' and 'losing face' on the international level (much like how some nations use & support terrorist networks--the whole 'my enemies enemy is my friend' thing). Just my thoughts on national security & missile defenses.