Excerpts from Books and Wikipedia
"The USSR's grip had seemed to loosen when Khrushchev denounced Stalin and Prime Minister Imre Nagy introduced some progressive reforms in Hungary, but a crackdown followed and Nagy was expelled from the party. . . . Nagy formed a new government, but when he announced Hungary's imminent withdraw from the Warsaw Pact, it was the last straw for Moscow. . . . The Hungarian Rising saw at least 3000 people killed and 13,000 wounded. Nagy was captured by the KGB, tried, and shot. October 23 had been a false dawn, or perhaps a rehearsal for the overthrow of communism in Hungary in 1989 to 1990." [Furtado: 1001 Days]