The likely political consequences of reunification also raised concerns. Some conservative South Koreans worry about adding millions of voters raised as socialists. The latter might reject communism, but still vote left. Thus, uniting the peninsula could backfire against those who most opposed the current North Korean regime.

Moreover, it is hard to imagine how reunification could occur voluntarily. In 1972 the two Koreas agreed to principles for reunification, but, as expected, nothing came of it. Although Koreans North and South share a common heritage, their cultures, economies, and political systems differ dramatically. Most important is the question of power. When I first visited the North 25 years ago, North Korean officials told me that they did not want to be “swallowed.” They understood that in any genuine reunification the DPRK would simply disappear. And with it their privileged positions.

Indeed, most would have no useful role in a new united Korea. South Koreans would flood in with money as newly empowered North Koreans defenestrated their former overlords. North Korean elites would end up at the bottom in a united Korea. They have no incentive to consent to their demise.