A military confrontation could start with a U.S. effort to force regime change, either by taking out the Kim regime or by fomenting a rebellion among elites in the isolated dictatorship.

“But it’s hard to imagine that scenario ending with anything other than the North Koreans deciding to light up Seoul,” Nephew said. And if South Korea were given a voice in any U.S. decision to use force, it’s unlikely that Seoul would assent to a strategy that could spark a wider conflagration on the Korean Peninsula.

Most of those who have considered the merits of launching a limited attack on the North — say, to destroy nuclear capabilities — have concluded that what Americans might see as limited could well be interpreted by the Kim regime as an invitation to all-out conflict.