Plenty of doubts have been raised about claims that North Korea executed its defense minister by anti-aircraft gun at the end of April. Whether or not Gen.Hyon Yong Chol met such a grisly end, though, the fact remains that top officials face increasingly uncertain fates in Pyongyang. Since coming to power three years ago, dictator Kim Jong Un has presided over a large and very violent purge of North Korea's military and civilian leadership. Some 70 high-level officials and generals have reportedly been executed during Kim's brief reign.

This marks a dramatic reversal of the strategies Kim's father and grandfather used to stay in power. As dictators' courts go, the palaces of Kim Il Sung and Kim Jong Il were remarkably safe places for their inner circle. After an initial period in which he exterminated all hostile factions, Kim Il Sung surrounded himself almost exclusively by the former guerrillas who had fought under his command in 1930s Manchuria.

North Korea's founder was relatively forgiving of trespasses. Disgraced officials might lose their jobs and disappear, but then in many cases reappeared a few years later back in the top ranks of the state and party hierarchy. The system encouraged loyalty. While a general or minister might suddenly find himself a clerk in a rural office or even a miner, he also knew that if he braced himself for humiliation and kept professing his devotion to the regime, he'd likely survive and prosper again.