In addition, any summit meeting cannot allow Mr. Pence’s pronouncements during the Olympics about North Korea’s human rights abuses to evaporate into thin air. Indeed, engaging the regime on improving its human rights record could be an important metric of the authenticity of the North’s diplomatic overtures.

Finally, everyone should be aware that this dramatic act of diplomacy by these two unusual leaders, who love flair and drama, may also take us closer to war. Failed negotiations at the summit level leave all parties with no other recourse for diplomacy. In which case, as Mr. Trump has said, we really will have “run out of road” on North Korea.