treaty we have a military alliance. we've got nearly 30,000 troops. so any armed conflict would inevitably involve the united states. more over, with their nuclear capabilities, the north koreans do given their track record of having sold weapons to all sorts of bad guys around the world, there is always the potential they might sell nuclear technology or material to a state the united states doesn't want to visit. recently you have had a conservative government in south korea that has been very tough on north korea, and north korea itself is going through a transition as their dictator kim jong-il tries to arrange for his son, kim jong un to secede him. it makes the situation very volatile. >> that succession issue in north korea front and center in this crisis. mike wrote meltdown, the inside story of the north korean nuclear crisis. thanks for joining us on cnn,