Eighty years ago, Joseph Stalin’s Great Terror (to use Robert Conquest’s term) was well into its first month. In towns and cities throughout the Soviet Union, the headquarters of the NKVD—the secret police—were filled with screams, the sounds of beatings and the clacking of typewriters. In the Kremlin, Stalin signed “shooting lists” of prominent Bolsheviks to be executed. Extrajudicial troikas provided a thin veneer of “socialist legality” as they rubber stamped death sentences.

The Great Terror was initiated by Stalin in his order on July 2, 1937, telling regional bosses to submit lists of “enemies of the people.” The NKVD’s infamous Order No. 00447, which followed on July 30, allotted quotas for 75,950 executions and 193,000 prison sentences. These “limits” were forgotten as regions competed for higher victim totals. By the time Stalin ended the purge with a single telegram on Nov. 17, 1938, 687,000 had been shot. Stalin pleaded innocence: Mavericks in the NKVD were to blame, he claimed.

Subsequent horrors in China, Cambodia and North Korea demonstrate that the Great Terror of 1937-38 was not the product of one man’s paranoia. What Stalin did was entirely “rational” for an absolute dictator with no moral qualms. It was perfectly fine, Stalin asserted, to kill 19 innocents as long as the 20th was an actual enemy. Instead of minimizing false convictions, as Western jurisprudence does, the system minimized false acquittals. After all, that one enemy left alive could end up being Stalin’s assassin.

After Stalin’s death in 1953, the U.S.S.R. moved to “lesser terror.” Soviet leaders had learned to be wary of becoming victims themselves. Besides, political enemies could be controlled in other ways, such as by denying benefits like higher education, travel or medical assistance. Prominent opposition leaders, such as Andrei Sakharov, were treated harshly behind closed doors in mental institutions, but they were not routinely killed. Relatives and children of nonconformists were disadvantaged, their life chances limited. Under such pressure, few people were willing to stand up and challenge the Soviet system outright.

The instruments of lesser terror are still routinely employed today. Vladimir Putin uses them to stay in power despite a weak economy, rising poverty and rampant corruption. The Kremlin allots state assets, government credits and university deanships to those in favor. Streaks of independence or defiance are punished by charges of corruption, confiscatory taxes and denial of business licenses. Political opponents are disqualified from the ballot, and ordinary protesters are sent to prison or put under house arrest. Anti-riot forces are given free rein to fire on demonstrators. Dissidents who become a real danger can be shot or poisoned. The murderer will never be found, despite an elaborate investigation and court proceeding.