cause in the Spanish Civil War. Great Purge The Great Purge mainly operated from December 1936 to November 1938, although the features of arrest and summary trial followed by execution were well entrenched in the Soviet system since the days of Lenin as Stalin systematically destroyed the older generation of pre-1918 leaders. Stalin did so usually under the justification that the accused were enemy spies or deemed "enemies of the people"; in the Red Army, a majority of generals were executed and hundreds of thousands of other "enemies of the people" were sent to the gulag, where inhumane conditions in Siberia led a quick death. The opening of the Soviet archives has vindicated the lower estimates put forth by the "revisionist school" scholars, despite the popular press continuing to use higher estimates and containing serious errors. By 2009, historian Archie Brown reported that estimates were now lower; about 1.7 million were arrested in 1937–1938 and half were shot. Pre-war dissident communists The International Right Opposition and Trotskyism are examples of dissidents who still claim communism today, but they are not the only ones. In Germany, the split in the SPD had initially led to a variety of Communist unions and parties forming which included the councilist tendencies of the AAU-D, AAU-E and KAPD. Councilism had a limited impact outside of Germany, but a number of international organisations formed. In Spain, a fusion of left and right dissidents led to the formation of the POUM. Additionally, the Spanish CNT was associated with the development of the FAI political party, a non-Marxist party which stood for revolutionary communism. Spreading communism (1945–1957) As the Cold War took effect around 1947, the Kremlin set up new international coordination bodies including the World Federation of Democratic Youth, the International Union of Students, the World Federation of Trade Unions, the Women's International Democratic Federation and the World Peace Council. Malcolm Kennedy says the "Communist 'front' system included such international organizations as the WFTU, WFDY, IUS, WIDF and WPC, besides a host of lesser bodies bringing journalists, lawyers, scientists, doctors and others into the widespread net". The World Federation of Trade Unions (WFTU) was established in 1945 to unite trade union confederations across the world and it was based in Prague. While it had non-communist unions it was largely dominated by the Soviets. In 1949 the British, American and other non-Communist unions broke away to form the