The Prague Spring. Warsaw Pact countries invades Czechoslovakia
The Prague Spring (Czech: Pražské jaro, Slovak: Pražská jar) was a period of political liberalization in Czechoslovakia during the era of its domination by the Soviet Union after World War II. It began on 5 January 1968, when reformist Alexander Dubček was elected First Secretary of the Communist Party of Czechoslovakia (KSČ), and continued until 21 August when the Soviet Union and other members of the Warsaw Pact invaded the country to halt the reforms.
The Prague Spring reforms were a strong attempt by Dubček to grant additional rights to the citizens of Czechoslovakia in an act of partial decentralization of the economy and democratization. The freedoms granted included a loosening of restrictions on the media, speech and travel. After national discussion of dividing the country into a federation of three republics, Bohemia, Moravia-Silesia and Slovakia, Dubček oversaw the decision to split into two, the Czech Republic and Slovak Republic. This was the only formal change that survived the end of Prague Spring, though the relative success of the nonviolent resistance undoubtedly prefigured and facilitated the peaceful transition to liberal democracy with the collapse of Soviet hegemony in 1989.
The reforms, especially the decentralization of administrative authority, were not received well by the Soviets, who, after failed negotiations, sent half a million Warsaw Pact troops and tanks to occupy the country. A large wave of emigration swept the nation. A spirited non-violent resistance was mounted throughout the country, involving attempted fraternization, painting over and turning street signs (on one occasion an entire invasion force from Poland was routed back out of the country after a day's wandering), defiance of various curfews, etc. While the Soviet military had predicted that it would take four days to subdue the country the resistance held out for eight months, and was only circumvented by diplomatic stratagems (see below). There were sporadic acts of violence and several suicides by self-immolation (such as that of Jan Palach), but there was no military resistance. Czechoslovakia remained controlled until 1989, when the velvet revolution ended pro-Soviet rule peacefully, undoubtedly drawing upon the successes of the non-violent resistance twenty years earlier. The resistance also became an iconic example of civilian-based defense, which, along with unarmed civilian peacekeeping constitute the two ways that nonviolence can be and occasionally has been applied directly to military or paramilitary threats.
After the invasion, Czechoslovakia entered a period of normalization: subsequent leaders attempted to restore the political and economic values that had prevailed before Dubček gained control of the KSČ. Gustáv Husák, who replaced Dubček and also became president, reversed almost all of Dubček's reforms. The Prague Spring inspired music and literature such as the work of Václav Havel, Karel Husa, Karel Kryl, and Milan Kundera's novel The Unbearable Lightness of Being.
Sources: wikipedia.org, news.lv