The man needs a bullet in his head. Take him out of the equation, sweep his underlings to prison and take away EVERY large weapon and destroy the country's nuclear capabilities.
If Kim Jong Un builds or deploys a nuclear missile advanced enough to pinpoint anywhere, do you think the world was right in simply condemning their program or will we be regretting not doing more? What would you do now, given the power?
Well, a catch-22 -damned if you do, damned if you don't.
Kim is a laughingstock, he's arrogant and a megalomaniac, but he's not entirely stupid. He's on a mission for respect, and he wants to hurt the Great Enemy. His homeland is programmed to his whim, and the penalty for anything short of worshipping him is unfailingly grim. Imagine a Hitler who didn't have to work for power.
Given the power to act, I would see that any weapons he made would be immediately destroyed by whatever means could be marshaled. A concerted effort to assassinate Kim would be undertaken. But that's just me.
I suspect that's the Feds knocking, gotta go....
I suppose it comes down to the adage that you can't convict a man of a crime merely because he's thinking about it; he actually has to act on his thoughts before he breaks the law.
Of course, if a criminal is conspiring to break the law that opens more options for the police to act and this has been seen many times post-9/11 in the hunt for wanna-be terrorists.
One of the problems with Kim is that he's posturing. He's a boy wearing his father's discarded boots and he desperately wants to be a man. That makes him unpredictable and a nice, neat assassination (preferably by his own people) would go a long way toward solving the problem. If his position was usurped by another unstable character -- and the PRK has plenty of those -- we would be no further ahead.
It would be nice if we could exercise the Atlantis option: saw Korea in halves across the 38th parallel and allow the north to sink below the waves.
Until then all we can do is carry on as though life was normal and keep our fingers crossed. Religious people could pray, which would be equally effective.