The term "repression" was officially used to describe the prosecution of people considered counter-revolutionaries and enemies of the people by the leadership of the Soviet Union at the time, Joseph Stalin. The purge was motivated by the desire to remove dissenters from the Communist Party and to consolidate the authority of Stalin. Most public attention was focused on the purge of certain parts of the leadership of the Communist Party, as well as of government bureaucrats and leaders of the armed forces, most of whom were Party members. The campaigns also affected many other categories of the society: intelligentsia, peasants and especially those branded as "too rich for a peasant" (kulaks), and professionals. A series of NKVD operations affected a number of national minorities, accused of being "fifth column" communities. A number of purges were officially explained as an elimination of the possibilities of sabotage and espionage, by the Polish Military Organisation and, consequently, many victims of the purge were ordinary Soviet citizens of Polish origin.
According to Nikita Khrushchev's 1956 speech, "On the Cult of Personality and its Consequences," and Robert Conquest, a great number of accusations, notably those presented at the Moscow show trials, were based on forced confessions, often obtained through torture, and on loose interpretations of Article 58 of the RSFSR Penal Code, which dealt with counter-revolutionary crimes. Due legal process, as defined by Soviet law in force at the time, was often largely replaced with summary proceedings by NKVD troikas.
Hundreds of thousands of victims were accused of various political crimes (espionage, wrecking, sabotage, anti-Soviet agitation, conspiracies to prepare uprisings and coups); they were quickly executed by shooting, or sent to the Gulag labor camps. Many died at the penal labor camps of starvation, disease, exposure, and overwork. Other methods of dispatching victims were used on an experimental basis. Some secret policeman, for example, gassed people to death in batches in the back of a specially adapted airtight van.
The Great Purge was started under the NKVD chief Genrikh Yagoda, but the height of the campaigns occurred while the NKVD was headed by Nikolai Yezhov, from September 1936 to August 1938, hence the name Yezhovshchina. The campaigns were carried out according to the general line, and often by direct orders, of the Party Politburo headed by Stalin.