The entry of five Warsaw Pact armies on to Czechoslovak soil in August 1968 prevented the continuation of the country's social reforms. After the intervention the Soviet leadership, in co-operation with other Warsaw Pact leaders, continued to pressure the leadership of the Communist Party of Czechoslovakia (CPC), the government and the parliament to prevent further reforms. These pressures led to the Moscow Protocol, which defined Czechoslovakia's new limited sovereignty. The Agreement on the Stationing of Soviet Forces, which gave no date for their departure, legitimised their presence on the territory of Czechoslovakia until the eventual collapse of the Communist regime. The leaders of the Warsaw Pact, with the support of conservative and pro-occupation forces, then planned to expel the representatives of reformist communism from leading positions in the CPC, government and parliament.

The era of ‘normalisation’

By the autumn of 1968, the campaign led by domestic conservative Communists was primarily directed at Josef Smrkovský, who was the chairman of parliament. As a result of Soviet pressure the leadership of the CPC did not repropose Smrkovský for the post at the end of 1968. The campaign unleashed to discredit Smrkovský was, at the same time, discrediting reformist communism in general. The second victim of Soviet pressure was Alexander Dubček, who was forced to resign as first secretary of the Central Committee of the CPC in mid April 1969.

With Gustáv Husák's assumption of the top position in the Communist Party, the era of ‘normalisation’ got underway.