A historian’s overview of Czechoslovakia’s Alexander Dubček, the Prague Spring of 1968, and the Warsaw Pact Invasion.   Cold War nadir: January 1968 and in Czechoslovakia, the new Communist Party leader, Alexander Dubcek, has made it clear that this is the opportunity to loosen the Soviet stranglehold on the country. As the Prague winter slowly eases into a Prague spring, it really does seem as if Dubček has judged it right. Reforms in oppressive censorship laws, improved housing, a lessening of totalitarian oppression, Dubček promises and delivers on it all. The new regime in Czechoslovakia does seek to destroy communism but it does want to choose its own political destiny.   And then, on the night of 20/21 August, the Prague Spring is crushed by the Warsaw Pact invasion: 200, 000 Communist troops, mostly Soviet but also Polish and East German, flood the country. The resulting protests and rallies against the invasion, mostly by young people, are violent and bloody. Hundreds die in clashes; self-immolation, in public and before the eyes of the world, brings home the horror and the depth of feeling in the Czech people.   It is the end of the Prague Spring, the reformation of Czechoslovakia having ended in ruins. But despite the brutal crushing of Czech hopes and dreams, the events of 1968 lay the foundations for future change. It will take another two decades but it is, ultimately, where the unraveling of the Communist bloc begins.