A striking feature of North Korean communism has been the remarkable measure of physical security enjoyed by the uppermost reaches of the brutal and repressive regime.

Elsewhere in the communist world, the highest tiers always enjoyed physical comforts. But the tumultuous, cutthroat nature of communist politics meant that their physical fate, up to and including cause of death, remained perilously contingent. (As the Bo Xilai affair in China underscores, this is still the case under “reform socialism”.) By contrast, North Korea’s “Great Leader” Kim Il Sung laid down a system of dynastic succession that protected not only the revolutionary royals but also those aristocrats closest to them.

Consider the case of Choe Kwang, chief of the general staff of the North Korean People’s Army in the late 1960s. In 1968, Kim Il Sung personally denounced Choe for “anti-party activities”, and the man disappeared. Under Stalin or Mao, those particulars would have been a death sentence. Yet Choe — whose family had close connections to the Great Leader’s — not only lived but went on to prosper. By the late 1980s, Choe was once again chief of the army general staff. By 1997, when he died of natural causes, he had been elevated to defence minister.

To be sure North Korean generals and other functionaries to Pyongyang’s royals have ended up in front of firing squads. But top families were exposed only sparingly to the routinised violence and terror they counted on to maintain their rule — and often transgressions that would have resulted in the ultimate sanction for commoners were pardoned or ignored for blue bloods. Unlike the French Revolution, which was famously said to “devour its own children”, and almost any other communist revolutionary descendants, the North Korean model, until this week, had followed Kim Il Sung’s hallowed injunction to grant “special favours” to “those who have performed feats for reunification of the country [and to] their descendants.”

This brings us to the defenestration of Jang Song Thaek, Pyongyang’s putative second in command, by Kim Jong Un, the young Dear And Respected Leader who is Kim Il Sung’s grandson and Jang’s nephew. On Monday, before a hall packed by his Politburo comrades, a passive Jang was repeatedly denounced for “anti-party activities” and other crimes, then frog-marched out of the chamber by uniformed guards. On Thursday, North Korean media announced the execution of “traitor for all ages Jang Song Thaek”.

This spectacle of public humiliation — and liquidation — of a royal marks a radical departure from business as usual. The North Korean state has its internal code of honour, and its paramount precept had always been that The Royals Stay Safe. But no longer can a regent and adviser in chief like Jang expect to be pensioned off to some posh inconsequential place once his services are no longer needed. Palace politics have suddenly become life-and-death.— By arrangement with the Washington Post-Bloomberg News Service