For Kim Jong Il, nuclear weapons provide a means to preserve his fiefdom. They generate international tension that justifies the garrison state. They compensate for conventional military weaknesses, providing a hedge against perceived U.S. military designs. They furnish leverage to extract international humanitarian assistance and economic investment from a nervous South Korea. And they provide an economically failing regime a marquee to demonstrate strength, resolve and modernity.
Full analysis by former Bush-1 State Department official Bennett Ramberg here.