Ash Carter: “I agree with everything I said then, including the need to do what we've done this past year.”

"Up-or-out" isn't broken--in fact, it's an essential and highly successful system--but it's also not perfect.

The international community, United Nations Security Council and especially the other six-party powers must hold North Korea accountable for this latest act and heighten the pressure on North Korea.

It absolutely is. That's why we quadrupled the European Reassurance Initiative.

China has and shares important responsibility for this development and has an important responsibility to reverse it.