In 1921, factions were banned in the Russian Communist Party (Bolsheviks). Since 1920 a majority of the Congress of the Communist Party of the Soviet Union had become concerned about oppositionist groups within the Communist Party. For example, the Democratic Centralists had been set up in March 1919 and by 1921 Alexander Shlyapnikov had set up the Workers' Opposition. The Congress regarded these as distractions within the party when unity was needed in order to neutralise the major crises of 1921, such as the famines, and Kronstadt Rebellion. Factions were also commencing to criticize Lenin's leadership. Consequently, the 10th Party Congress passed a Resolution On Party Unity, a ban on factions to eliminate factionalism within the party in 1921. The resolution stated as follows. Under the present conditions (apparently, the ongoing Kronstadt rebellion), party unity was more necessary than ever. The Kronstadt rebellion was being exploited by "the bourgeois counter-revolutionaries and whiteguards in all countries of the world" in order to "secure the overthrow of the dictatorship of the proletariat in Russia". Criticism, "while absolutely necessary", was supposed to be "submitted immediately, without any delay", that is, without prior deliberation in any faction, "for consideration and decision to the leading local and central bodies of the Party." The "deviation towards syndicalism and anarchism" was rejected "in principle", but the central proposals of the Democratic Centralism group were accepted. All factions were dissolved. Faction members (such as members of "Workers' Truth") would be expelled from the Party in December 1923. Big opposition factions (such as Leon Trotsky's 'Left Opposition' and such as oppositionist groups around Nikolai Bukharin and Grigory Zinoviev) again appeared after the civil war ended. These factions were tolerated for several years, leading some modern Marxists to claim that the ban on factions was intended to be temporary.