In the past two decades, at least two terrorist groups have made serious attempts at obtaining nuclear weapons or the nuclear material needed to make them. They won't be the last. Foiling terrorists willing to inflict unlimited damage requires the international community to prioritize the nuclear stocks that pose the greatest risks and take immediate steps to eliminate or secure them.

Eben Harrell published an op-ed on TIME.com about Kim Jong Il's nuclear proliferation legacy.

"Nuclear proliferation is a crime that pays well. Those involved in the Khan network were made very wealthy for their efforts, and the inability of the international community to effectively punish them has resulted in a missed opportunity to provide a deterrent against future black-market salesmen."