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Education and early political career

In 1948, the party he had joined was reorganized as the Slovak branch of the Communist Party of Czechoslovakia (KSČ). Though still outside of the higher circles, Dubček's generation represented the young idealistic rank-and-file of the party that took power in 1948, not a break from it. It was Stalinism that represented the discontinuity. It was this pre-Stalinist generation that originally seized power, allied with the younger generation of party members, who began to question the path taken by their leadership elders as they began to rise in the ranks during the 1950s and early 1960s.

The Slovak branch of the party emerged from the war with a smaller membership base and less connection with Slovak institutions than the Czech branches had. To recruit a mass party base for electoral politics, the party's leadership, which was over 60 years old on average, appealed to a broad segment of less ideologically motivated younger people, giving the party a more pragmatic and less orthodox culture. In contrast to the Czech branch of the party, family, regional identity, religious, professional, and inter-personal relationships formed the glue of the Slovak branch of the party. A socially idealistic Dubček, with no rigid ideological destination in mind, rose amid these ranks.

In 1948, the Communist Party of Czechoslovakia took power. In June, 1949, still in Trenčín, Dubček was promoted from his minor party duties at his workplace to administrative secretary of the OV KSS. He rose through the party ranks as a party functionary, first in Trenčín, then being transferred to Bratislava, and then to Banská Bystrica, while he pursued further education and training. He left for the Soviet Union in 1955, but returned in 1958 after completing his university education there. Shortly after returning from Moscow, in September 1958 he was appointed head secretary of the West Slovak Regional Committee of the KSS, and then transferred to Prague in 1960. There, as Secretary of the Central Committee of the Communist Party of the Czech Republic for Industry, Dubček became intensely involved in the work of rehabilitation commissions (especially Drahomir Kolder's and Barnabit's, 1962–1963). Learning of the mechanisms of repression, Dubček would call this a watershed in his thinking that would dedicate him to reforms.

From 1960 to 1968, he also participated in the National Assembly.

In 1963, a power struggle in the leadership of the Slovak branch unseated Karol Bacílek and Pavol David, hard-line allies of Antonín Novotný, First Secretary of the KSČ and President of Czechoslovakia. Bacílek was removed in response to the findings of the rehabilitation commissions, due to his role in crimes as Interior Minister in the 1950s. In their place, a new generation of Slovak Communists took control of party and state organs in Slovakia, led by Dubček, who became First Secretary of the Slovak branch of the party. Along with that title, Dubček became a member of the Presidium of the Central Committee of the KSČ.

Shortly after Dubček took his new position as head of the Slovak party in 1963, he personally oversaw complete rehabilitation of those earlier convicted of being Slovak "bourgeois nationalists". He promoted the return of historic cultural personalities to popular awareness within Slovak society. This took the form of celebrations and commemorations, such as the 150th birthdays of 19th century leaders of the Slovak National Revival Ľudovít Štúr and Jozef Miloslav Hurban, the centenary of the Matica slovenská in 1963, and the twentieth anniversary of the Slovak National Uprising Dubček himself had taken part in. Even before this reformist take-over, the political and intellectual climate in Slovakia had been freer than that in the Czech lands.

Meanwhile, cultural weeklies such as Literarni Novinv, Kultúrny život,, and Kulturni Tvorba saw greatly expanded readership. Like many of the Slovak culture institutions, these publications were, however, engaged in a mostly indirect confrontation with the center, such as obvious ironic overstating of the party line. Political conflicts were commonly negotiated. This was complicated by exceptions, such as Kultúrny život, the weekly newspaper of the Union of Slovak Writers, which authorities considered politically unreliable. Such direct confrontations were spreading. In 1967, Vaclav Havel's play, The Memorandum, Milan Kundera 's novel, The Joke (novel), were seen by many writers as the beginnings of open rebellion.