The Great Purge or the Great Terror, also known as the Year of '37 and the Yezhovschina ('period of Yezhov'), was a campaign of political repression and state terrorism ordered by Joseph Stalin in the Soviet Union that occurred from 1936 to 1938. It involved a large-scale repression of wealthy peasants, known as "kulaks"; genocidal acts against ethnic minorities; a purge of the Communist Party of the Soviet Union, government officials, and the Red Army leadership; widespread police surveillance; suspicion of saboteurs; counter-revolutionaries; imprisonment; and arbitrary executions. Historians estimate the total number of deaths due to Stalinist repression in 1937–38 to be between 680,000 and 1,200,000.
The "Kulak Operation" and the targeting of national minorities were the main components of the Great Terror. Together these two actions accounted for nine-tenths of the death sentences and three-fourths of Gulag prison camp sentences. Of the operations against national minorities, the Polish Operation of the NKVD was the largest one, second only to the "Kulak Operation" in terms of the number of victims. According to historian Timothy Snyder, ethnic Poles constituted the largest group of victims in the Great Terror, comprising less than 0.5% of the country's population but comprising 12.5% of those executed. Timothy Snyder attribute 300,000 deaths during the Great purge to "national terror" including ethnic minorities and Ukrainian Kulaks who survived the early 1930s.
In the Western world, Robert Conquest's 1968 book The Great Terror popularized the phrase. Conquest's title itself was an allusion to the period from the French Revolution known as the Reign of Terror (French: la Terreur, "the Terror"; from June to July 1794: la Grande Terreur, 'the Great Terror'). In writing the book, however, Robert Conquest never actually visited or tried to visit the USSR. While Norman Naimark deemed Stalin's 1930s Polish policy "genocidal", he did not consider the entire Great Purge genocidal because it also targeted political opponents
From 1930 onwards, the Party and police officials feared the "social disorder" caused by the upheavals of forced collectivization of peasants and the resulting famine of 1932–1933, as well as the massive and uncontrolled migration of millions of peasants into cities. The threat of war heightened Stalin's perception of marginal and politically suspect populations as the potential source of an uprising in case of invasion. He began to plan for the preventive elimination of such potential recruits for a mythical "fifth column of wreckers, terrorists and spies."
The term "purge" in Soviet political slang was an abbreviation of the expression purge of the Party ranks. In 1933, for example, the Party expelled some 400,000 people. But from 1936 until 1953, the term changed its meaning, because being expelled from the Party came to mean almost certain arrest, imprisonment, and often execution.
The political purge was primarily an effort by Stalin to eliminate challenge from past and potential opposition groups, including the left and right wings led by Leon Trotsky and Nikolai Bukharin, respectively. Following the civil war and reconstruction of the Soviet economy in the late 1920s, veteran Bolsheviks no longer thought necessary the "temporary" wartime dictatorship, which had passed from Vladimir Lenin to Stalin. Stalin's opponents on both sides of the political spectrum chided him as undemocratic and lax on bureaucratic corruption. This opposition to current leadership may have accumulated substantial support among the working class by attacking the privileges and luxuries the state offered to its high-paid elite. The Ryutin Affair seemed to vindicate Stalin's suspicions. He enforced a ban on party factions and banned those party members who had opposed him, effectively ending democratic centralism.
In the new form of Party organization, the Politburo, and Stalin in particular, were the sole dispensers of ideology. This required the elimination of all Marxists with different views, especially those among the prestigious "old guard" of revolutionaries. As the purges began, the government (through the NKVD) shot Bolshevik heroes, including Mikhail Tukhachevsky and Béla Kun, as well as the majority of Lenin's Politburo, for disagreements in policy. The NKVD attacked the supporters, friends, and family of these "heretical" Marxists, whether they lived in Russia or not. The NKVD nearly annihilated Trotsky's family before killing him in Mexico; the NKVD agent Ramón Mercader was part of an assassination task force put together by Special Agent Pavel Sudoplatov, under the personal orders of Stalin.
In 1934, Stalin used the murder of Sergey Kirov as a pretext to launch the Great Purge, in which about a million people perished. Some later historians came to believe that Stalin arranged the murder, or at least that there was sufficient evidence to reach such a conclusion. Kirov was a staunch Stalin loyalist, but Stalin may have viewed him as a potential rival because of his emerging popularity among the moderates. The 1934 Party Congress elected Kirov to the central committee with only three votes against, the fewest of any candidate, while Stalin received 292 votes against. After Kirov's assassination, the NKVD charged the former oppositionists, an ever-growing group according to their determination, with Kirov's murder as well as a growing list of other offences, including treason, terrorism, sabotage, and espionage.
Another justification for the purge was to remove any possible "fifth column" in case of a war. Vyacheslav Molotov and Lazar Kaganovich, participants in the repression as members of the Politburo, maintained this justification throughout the purge; they each signed many death lists. Stalin believed war was imminent, threatened both by an explicitly hostile Germany (now under the leadership of Adolf Hitler and his Nazi Party) and an expansionist Imperial Japan. The Soviet press portrayed the country as threatened from within by fascist spies.
From the October Revolution onward, Lenin had used repression against perceived enemies of the Bolsheviks as a systematic method of instilling fear and facilitating social control, especially during the campaign commonly referred to as the Red Terror. This policy continued and intensified under Stalin, periods of heightened repression including the deportation of kulaks who opposed collectivization, and a severe famine in Ukraine. Lev Kopelev wrote, "In Ukraine 1937 began in 1933," referring to the comparatively early beginning of the Soviet crackdown in Ukraine. A distinctive feature of the Great Purge was that, for the first time, members of the ruling party were included on a massive scale as victims of the repression. Due to the scale of the terror, the substantial victims of the purges were Communist Party members and office-holders. The purge of the Party was accompanied by the purge of the whole society.