Almost all citizens of the former Czechoslovakia are familiar with the events of 1968. Around 60 per cent of Czech respondents in a 1993 survey had a personal memory of the Prague Spring, and another 30 per cent knew of it from history books, the media, or family lore. Yet there is a striking lack of consensus among them on why the Soviet Union decided to intervene with massive force in August. Thirty per cent attributed it to the Soviet Union's national interest as a superpower, 12 per cent ascribed it to fear of the collapse of the Warsaw Pact, and 4 per cent blamed it on Soviet rivalry with the West. For 21 per cent it was intended to preserve communist rule in Czechoslovakia, and another 12 per cent saw it as motivated by a desire to suppress democracy and freedom. Three per cent viewed the invasion positively as the defence of socialism, while 13 per cent could not identify a single reason.

Just as Czechs cannot agree, neither can scholars. Like many respondents, some authors emphasize the wider context of superpower relations on the eve of détente, and see the invasion as a move to tighten the Soviet grip before bargaining with the West and to seize an opportunity to station armies in Czechoslovakia. Soviet leaders indeed feared that, unchecked, Czechoslovakia might quit the socialist bloc, fall under West German influence, disrupt the post-war balance of power, and possibly endanger European security.