During his leadership, under the slogan "Socialism with a human face", Czechoslovakia lifted censorship on the media and liberalized Czechoslovak society, fueling the so-called New Wave in Czechoslovak filmography. However, he was put under pressure by Stalinist voices inside the party as well as the Soviet leadership, who disliked the direction the country was taking and feared that Czechoslovakia could loosen ties with the Soviet Union and become more westernized. As a result, the country was invaded by the other Warsaw Pact countries on 20–21 August 1968, ending the Prague Spring. Dubček resigned in April 1969 and was succeeded by Gustáv Husák, who initiated normalization. Dubček was then expelled from the Communist Party in 1970.