What do you mean by persistent containment? Short of war, I think North Korea has the upper hand. What if North Korea sells nukes? Or missiles (Supposedly, Iran’s Shihab-3 that successfully sent a satellite to space is a modified form of North Korea’s Rodong Missile, you can check fas.org or globalsecurity.org).
Only when it comes to war does the U.S. have the upper hand (and by far).
The weak link in Iran-N. Korea connection is the air shipment over China.
For other connection outside China, it should be contained.
Sustained sanction and containment, without rushed attempt to see any result soon, is the best way, especially now that Kim Jong-il's days are numbered.