If it is inevitable. That is a very, very big "if" and when we're talking about hundreds of thousands or even millions of lives that could be lost, it is good to make sure you are comfortable with the assessment that it is inevitable.

At this point, I don't see that North Korea is serious about engaging in Chinese-style economic reforms, which is really the only way that I can imagine North Korea evolving and the situation improving.

If China is unwilling to force the North to back down militarily and there is no interest on the North Korean side in reforming their society, then the North could very well represent the sort of ticking time bomb that is better set off in a controlled detonation now.

However, I'm not privy to the information to make the determination so I'll hope that the US is basing its decision on true information rather than blind speculation.