(ANSA) - PRAGUE - The spring of 1968 for Prague and for Czechoslovakia was the prelude to a hot summer and a freezing cold fall that would last twenty years. The dream of a ''socialism with a human face'' was crushed by the tanks of the Warsaw Pact on August 20, at night. A military invasion, passed off by the Kremlin's efficient ''dinsinformacja'' as a ''liberation'' from the ''counter-revolutionaries''. More than six thousand armored vehicles from the USSR, DDR, Poland, Hungary, Bulgaria (the Romanians had opted out) and about half a million soldiers broke through the Czechoslovak borders, which were defenseless because the army had been sent to the border with West Germany on the occasion of a military exercise that Moscow had already planned in May. All these things happened fifty years ago. The Czech Communist Party led by Alexander Dubek had just enough time to move up the 14th extraordinary congress scheduled for September and pass - held in a big locomotive factory on the outskirts of Prague - the Action Program issued on April 5 and already approved by the Central Committee: a radical plan to undertake structural reforms to the local economy and separate the party's role and power from institutional bodies and the government. The plan sounded like a full-blown heresy to Moscow and the Pcus, and was therefore viewed as unacceptable. On the morning of August 21 the streets of Prague were invaded by Soviet armored vehicles but they were also packed with people overwhelmed by the turn of events and determined not to suffer them. A crowd took to the streets and invaded Wenceslas Square.

The Soviets, who had been wlecomed as liberators from the Nazis in 1945, became invaders. On June 27, the ''The2000 Words manifesto'' written by the writer Ludvik Vasulik had been welcomed with enthusiasm by thousands of celebrities in the fields of culture, art and sport, with a strong demand for acceleration of the democratization process. In July, the Soviet press and that of the DDR had warned Prague about the risks of ''imperialism'', ''deviationism'' and ''counter-revolution''; on August 19, on the eve of the invasion, Brenev himself had written a letter to Dubek, in order to express his disappointment with what was happening in Czechoslovakia Hundreds were killed on both sides, but mainly on the side of the Czechoslovaks. The Western countries could only wait on the side-lines, express their sympathy and solidarity with an attacked people, but nothing else. The communist parties were forced to begin an examination of conscience, which was not always careful and faithful. The Soviet propaganda insisted that the country had been liberated from the counter-revolutionaries, the Prague radio continued to spread desperate messages addressed to the free Europe, exhorting not to believe in that manifestly untrue version of the facts. On 24 August, Dubek and other members of the Czechoslovak government were taken to Moscow and obliged to accept the presence of Warsaw Pact troops and renounce the reform program. The dream of spring in Prague evaporated and ''normalization'' began. On January 16, 1969, the university student Jan Palach, without saying a single word, poured petrol over himself and set fire to himself in Wenceslas Square. Hundreds of thousands of people attended his funeral, challenging the regime's power. On April 17, Dubek was ousted and his place taken by Gustav Husak. The current president of the Czech Republic, Milo Zeman, at that time was a young university professor who had refused to sign a document which claimed that the events of 21 August 1968 were a ''liberation'' and not an invasion. Thousands and thousands of Czechoslovaks did the same thing, and not only the intellectuals. The famous Olympic champion Emil Zatopek, ''the human locomotive'', was sent to work in a uranium mine and after six years sent back to Prague to be a street sweeper. Zeman was expelled from professorship in 1970. Through his spokesperson he made known his intention not to give any commemorative or celebratory speech, since he had already said what he had to say fifty years earlier, 'when you needed to have a lot of courage and you had to pay a very high price: a thousand speeches given today are not worth the few respectable words we said at that time'. (ANSA).