Rationally speaking, then, South Korea should be open to some kind of reconciliation framework that leaves the two states largely intact while symbolically proclaiming unification and an end to the Korean War. If it’s concerned primarily with regime survival — which the preponderance of evidence suggests is the case — then North Korea should be amenable to something similar. So what’s the problem?

Well, where would such an endgame leave the United States?

It is vanishingly unlikely that North Korea — or its Chinese allies — would agree to any formal program for reunification while American troops remained in South Korea and our alliance remained intact. North Korea built its nuclear deterrent in the first place because, in the wake of the collapse of the Soviet Union, there was ample reason to believe that the United States would seek to resolve the long-dormant Korean conflict by force. And much of America’s foreign policy since the end of the Cold War — from incorporation of a reunified Germany, the Warsaw Pact states and the Baltic republics into NATO, to the two wars in Iraq, to the intervention in Libya — has given the Kim family every reason to believe that trusting America to respect North Korean independence or the Kim family’s interests would be folly.