In reality, the country was controlled extra-constitutionally by the Polish United Workers' Party, which used its own rules and practices to supervise all governmental institutions specified in the constitution. Stalin died in 1953, which was followed by a partial thaw in Poland. Nikita Khrushchev became first secretary of the Communist Party of the Soviet Union. The PZPR's Second Congress deliberated in March 1954. Cyrankiewicz, previously replaced as prime minister by Bierut, was returned to that post (to remain prime minister until December 1970). The Six-Year Plan was adjusted to increase production of items for popular consumption. Khrushchev, present at the Congress, asked Bierut for the reasons of the continuing detention of Gomułka, "a good communist"; Bierut denied having specific knowledge of Gomułka's imprisonment. Following the defection to the West and revelations of its official Józef Światło, the Ministry of Public Security was abolished in December 1954. Gomułka and his associates were freed from confinement and censorship was slightly relaxed. The two notable periodicals braving the prohibitions were Po prostu ('Simply') and Nowa Kultura ('The New Culture') (Po prostu was closed down and its defenders brutally pacified in October 1957, just one year after Gomułka's rise to power). From early 1955, the Polish press engaged in criticizing the Stalinist recent past and praising the older Polish socialist traditions (social democratic Marxism and national independence). Political discussion clubs were on the rise throughout the country. The party itself appeared to be moving in the social democratic direction. Leftist intellectuals, who had joined the party because of their commitment to social justice, were heading in the social democratic direction more decisively and they soon gave rise to the Polish revisionism movement. In February 1956, Khrushchev denounced Stalin's cult of personality at the 20th Congress of the Communist Party of the Soviet Union and embarked on a reform course. The de-Stalinization of official Soviet ideology left Poland's Stalinist hardliners in a difficult position. While unrest and desire for reform and change among both intellectuals and workers were beginning to surface throughout the Eastern Bloc, the death of Stalin's ally Bierut in March 1956 in Moscow (he was attending the Soviet party's congress) exacerbated an existing split in the Polish party. In March Bierut was succeeded by Edward Ochab as first secretary. As the 20th Congress inspired also partial democratisation of Polish political and economic life, Ochab engaged in reforms intended to promote industrial decentralization