A dozen years ago on a visit to North Korea I caught a glimpse of an unfamiliar phenomenon. A platoon of soldiers, away from their base for a day of R&R, marched toward me along a broad, marble-floored museum corridor. All of the young men were conspicuously short, several under five feet. I had heard about youngsters stunted by the horrible famine of the mid-1990s but, on previous trips, hadn’t been permitted to see the human evidence.