Russian President Vladimir Putin’s decision to order a full-scale invasion of Ukraine defies any and all political logic, even his own hardened authoritarian reasoning.

With his unprovoked assault, Putin joins a long line of irrational tyrants, not least Joseph Stalin, who believed that sustaining his power required a constant expansion of it. That logic led Stalin to commit horrific atrocities against his own people, including causing a famine that starved millions of Ukrainians to death.

Another 20th-century mass murderer, Mao Zedong, famously declared that political power grows out of the barrel of a gun — or, it seemed, a nuclear missile. Mao demanded that my great-grandfather, Soviet leader Nikita Khrushchev, provide China with nuclear weapons, so that Mao could effectively hold his adversaries, foreign and domestic, hostage.