Warsaw Pact invasion of Czechoslovakia On the night of 20 – 21 August 1968 , the Soviet Union and its main allies in the Warsaw Pact – Bulgaria , Hungary , East Germany , and Poland – invaded the Czechoslovak Socialist Republic in order to halt Alexander Dubček ' s Prague Spring political liberalisation reforms . In the operation , codenamed " Danube " , approximately 500 , 000 troops attacked Czechoslovakia ; approximately 500 Czechs and Slovaks were wounded and 108 killed in the invasion . The invasion successfully stopped the liberalisation reforms and strengthened the authority of the Communist Party of Czechoslovakia ( KSČ ) . The foreign policy of the Soviet Union during this era was known as the Brezhnev Doctrine . Soviet fears . Leonid Brezhnev and the leadership of the Warsaw Pact countries worried that the unfolding liberalizations in Czechoslovakia , including the ending of censorship and political surveillance by the secret police , would be detrimental to their interests . The first of such fears was that Czechoslovakia would defect from the bloc , injuring the Soviet Union ' s position in a possible war with the North Atlantic Treaty Organisation ( NATO ) . Not only would the loss result in a lack of strategic depth for the USSR , but it would also mean that it could not tap Czechoslovakia ' s industrial base in a potential war . Other fears included the spread of liberal communism and unrest elsewhere in Eastern Europe . The Warsaw Pact countries worried that if the Prague Spring reforms went unchecked , then those ideals might very well spread to Poland and East Germany , upsetting the status quo there as well . Within the Soviet Union , nationalism in the republics of Estonia , Latvia , Lithuania , and Ukraine was already causing problems , and many worried that events in Prague might exacerbate those problems . KGB chairman Yuri Andropov and Ukrainian leaders Petro Shelest and Nikolai Podgorny were the most vehement proponents of military intervention . In addition , part of Czechoslovakia bordered Austria and West Germany , which were on the other side of the Iron Curtain . This meant both that foreign agents could potentially slip into Czechoslovakia and into any member of the Communist Bloc and that defectors could slip out to the West . The final concern emerged directly from the lack of censorship ; writers whose work had been censored in the Soviet Union could simply go to Prague or Bratislava and air their grievances there , circumventing the Soviet Union ' s censorship . Czechoslovak negotiations with the USSR and other Warsaw Pact states . The Soviet leadership at first tried to stop or limit the impact of Dubček ' s initiatives through a series of negotiations . Czechoslovakia and the Soviet Union agreed to bilateral talks to be held in July 1968 at Čierna nad Tisou , near the Slovak - Soviet border . At the meeting , Dubček defended the programme of the reformist wing of the KSČ while pledging commitment to the Warsaw Pact and Comecon . The KSČ leadership , however , was divided between vigorous reformers ( Josef Smrkovský , Oldřich Černík , and František Kriegel ) who supported Dubček , and conservatives ( Vasil Biľak , Drahomír Kolder , and Oldřich Švestka ) who adopted an anti - reformist stance . Brezhnev decided on compromise . The KSČ delegates reaffirmed their loyalty to the Warsaw Pact and promised to curb " anti - socialist " tendencies , prevent the revival of the Czechoslovak Social Democratic Party , and control the press more effectively . The USSR agreed to withdraw their troops ( still stationed in Czechoslovakia since the June 1968 maneuvers ) and permit the 9 September party congress . On 3 August , representatives from the Soviet Union , East Germany , People ' s Republic of Poland , Hungary , Bulgaria , and Czechoslovakia met in Bratislava and signed the Bratislava Declaration . The declaration affirmed unshakable fidelity to Marxism - Leninism and proletarian internationalism and declared an implacable struggle against bourgeois ideology and all " antisocialist " forces . The Soviet Union expressed its intention to intervene in a Warsaw Pact country if a bourgeois system — a pluralist system of several political parties representing different factions of the capitalist class — was ever established . After the Bratislava conference , Soviet troops left Czechoslovak territory but remained along Czechoslovak borders . As these talks proved unsatisfactory , the USSR began to consider a military alternative . The Soviet Union ' s policy of compelling the socialist governments of its satellite state s to subordinate their national interests to those of the Eastern Bloc ( through military force if needed ) became known as the Brezhnev Doctrine . NATO . The United States and NATO largely turned a blind eye to the evolving situation in Czechoslovakia . While the Soviet Union worried it might lose an ally , the United States had absolutely no desire on gaining it . President Lyndon Johnson had already invested the United States in the Vietnam War and was unlikely to be able to drum up support for a potential conflict in Czechoslovakia . Also , he wanted to pursue an arms control treaty with the Soviets , SALT . He needed a willing partner in Moscow in order to reach such an agreement , and he did not wish to potentially risk that treaty for Czechoslovakia . For these reasons , the United States made it clear that it would not intervene on behalf of the Prague Spring , giving the USSR a free hand to do as it pleased . Intervention . At approximately 11 pm on 20 August 1968 , Eastern Bloc armies from four Warsaw Pact countries – the Soviet Union , Bulgaria , Poland and Hungary – invaded Czechoslovakia . That night , 200 , 000 Warsaw Pact troops and 2 , 000 tanks entered the country . Romania did not take part in the invasion , and neither did Albania , which withdrew from the Warsaw Pact over the matter . Participation of German Democratic Republic ( East Germany ) was cancelled just hours before the invasion . The invasion was well planned and coordinated , simultaneously with the border crossing by ground forces , a Soviet airborne division ( VDV ) captured Prague ' s Ruzyne International Airport in the early hours of the invasion . It began with a special flight from Moscow which carried more than 100 plainclothes agents . They quickly secured the airport and prepared the way for the huge forthcoming airlift , in which An - 12 transport aircraft started arriving and unloading Soviet airborne troops equipped with artillery and light tanks . As the operation at the airport continued , columns of tanks and motorized rifle troops headed toward Prague and other major centers , meeting no resistance . The bulk of invading forces were from the Soviet Union supported by other countries from the communist bloc . Among them were 28 , 000 troops of the Polish 2nd Army from the Silesian Military District , commanded by general Florian Siwicki , and all invading Hungarian troops were withdrawn by 31 October . During the attack of the Warsaw Pact armies , 72 Czechs and Slovaks were killed ( 19 of those in Slovakia ) and hundreds were wounded . Alexander Dubček called upon his people not to resist . He was arrested and taken to Moscow along with several of his colleagues . Dubček and most of the reformers were returned to Prague on 27 August , and Dubček retained his post as the party ' s first secretary until he was forced to resign in April 1969 following the Czechoslovak Hockey Riots . The invasion was followed by a wave of emigration , largely of highly qualified people , unseen before and stopped shortly after ( estimate : 70 , 000 immediately , 300 , 000 in total ) . Western countries allowed these people to immigrate without complications . Failure to prepare . The Dubcek regime took no steps to forestall a potential invasion , despite the ominous troop movements by the Warsaw Pact . The Czechoslovak leadership believed that the Soviet Union and its allies would not invade , having believed that summit at Čierna nad Tisou smoothed out the differences between the two sides . They also believed that any invasion would be too costly , both because of domestic support for the reforms and because the international political outcry would be too significant , especially with the World Communist Conference coming up in November of that year . Czechoslovakia could have raised the costs of such an invasion by drumming up international support or making military preparations such as blocking roads and ramping up security of their airports , but they decided not to , paving the way for the invasion . Letter of invitation . Although on the night of the invasion , the Czechoslovak Presidium declared that Warsaw Pact troops had crossed the border without knowledge of the ČSSR Government , the Soviet Press printed an unsigned request , allegedly by Czechoslovak party and state leaders , for " immediate assistance , including assistance with armed forces . " At the 14th KSČ Party Congress ( conducted secretly , immediately following the intervention ) , it was emphasized that no member of the leadership had invited the intervention . At the time , a number of commentators believed the letter was fake or non - existent . In the early 1990s , however , the Russian government gave the new Czechoslovak President , Václav Havel , a copy of a letter of invitation addressed to Soviet authorities and signed by KSČ members Biľak , Švestka , Kolder , Indra , and Kapek . It claimed that " right - wing " media were " fomenting a wave of nationalism and chauvinism , and are provoking an anti - communist and anti - Soviet psychosis . " It formally asked the Soviets to " lend support and assistance with all means at your disposal " to save the Czechoslovak Socialist Republic " from the imminent danger of counterrevolution . " A 1992 " Izvestia " article claimed that candidate Presidium member Antonin Kapek gave Leonid Brezhnev a letter at the Soviet - Czechoslovak Čierna nad Tisou talks in late July which appealed for " fraternal help . " A second letter was supposedly delivered by Biľak to Ukrainian Party leader Petro Shelest during the August Bratislava conference " in a lavatory rendezvous arranged through the KGB station chief . " This letter was signed by the same five as Kapek ’ s letter , mentioned above . Internal plot . Long before the invasion , planning for a coup was undertaken by Indra , Kolder , and Biľak , among others , often at the Soviet embassy and at the Party recreation centre at Orlík Dam . When these men had managed to convince a majority of the Presidium ( six of eleven voting members ) to side with them against Alexander Dubček ’ s reformists , they asked the USSR to launch a military invasion . The USSR leadership was even considering waiting until the 26 August Slovak Party Congress , but the Czechoslovak conspirators " specifically requested the night of the 20th . " The plan was to unfold as follows . A debate would unfold in response to the Kašpar report on the state of the country , during which conservative members would insist that Dubček present two letters he had received from the USSR , letters which listed promises he had made at the Čierna nad Tisou talks but had failed to keep . Dubček ’ s concealment of such important letters , and his unwillingness to keep his promises would lead to a vote of confidence which the now conservative majority would win , seizing power , and issue a request for Soviet assistance in preventing a counterrevolution . It was this formal request , drafted in Moscow , which was published in Pravda on 22 August without the signatories . All the USSR needed to do was suppress the Czechoslovak military and any violent resistance . With this plan in mind , the 16 – 17 August Soviet Politburo meeting passed a resolution to " provide help to the Communist Party and people of Czechoslovakia through military force . " At the 18 August Warsaw Pact meeting , Brezhnev announced that the intervention would go ahead on the night of 20 August , and asked for " fraternal support " , which the national leaders of Bulgaria , East Germany , Hungary , and Poland duly offered . Failure of the plot . The coup , however , did not go according to plan . Kolder intended to review the Kašpar report early in the meeting , but Dubček and Špaček , suspicious of Kolder , adjusted the agenda so the upcoming 14th Party Congress could be covered before any discussion on recent reforms or Kašpar ’ s report . Discussion of the Congress dragged on , and before the conspirators had a chance to request a confidence vote , early news of the invasion reached the Presidium . An anonymous warning was transmitted by the Czechoslovak Ambassador to Hungary , Jozef Púčik , approximately six hours before Soviet troops crossed the border at midnight . When the news arrived , the solidarity of conservative coalition crumbled . When the Presidium proposed a declaration condemning the invasion , two key members of the conspiracy , Jan Pillar and František Barbírek , switched sides to support Dubček . With their help , declaration against the invasion won with a 7 : 4 majority . The Moscow Protocol . By the morning of 21 August , Dubček and other prominent reformists had been arrested and were later flown to Moscow . There they were held in secret and interrogated for days . The conservatives asked Svoboda to create an " emergency government " but since they had not won a clear majority of support , he refused . Instead , he and Gustáv Husák traveled to Moscow on 23 August to insist Dubček and Černík should be included in a solution to the conflict . After days of negotiations , the Czechoslovak delegation accepted the " Moscow Protocol " , and signed their commitment to its fifteen points . The Protocol demanded the suppression of opposition groups , the full reinstatement of censorship , and the dismissal of specific reformist officials . It did not , however , refer to the situation in the ČSSR as " counterrevolutionary " nor did it demand a reversal of the post - January course . Reactions in Czechoslovakia . Popular opposition was expressed in numerous spontaneous acts of nonviolent resistance . In Prague and other cities throughout the republic , Czechs and Slovaks greeted Warsaw Pact soldiers with arguments and reproaches . Every form of assistance , including the provision of food and water , was denied to the invaders . Signs , placards , and graffiti drawn on walls and pavements denounced the invaders , the Soviet leaders , and suspected collaborationists . Pictures of Dubček and Svoboda appeared in the streets . Citizens gave wrong directions to soldiers and even removed street signs ( except for those giving the direction back to Moscow ) . Initially , some civilians tried to argue with the invading troops , but this met with little or no success . After the USSR used photographs of these discussions as proof that the invasion troops were being greeted amicably , secret Czechoslovak broadcasting stations discouraged the practice , reminding the people that " pictures are silent . " The protests in reaction to the invasion lasted only about seven days . Explanations for the fizzling of these public outbursts mostly center around demoralization of the population , whether from the intimidation of all the enemy troops and tanks or from being abandoned by their leaders . Many Czechoslovaks saw the signing of the Moscow Protocol as treasonous . Another common explanation is that , due the fact that most of the society was middle class , the cost of continued resistance meant giving up a cushy lifestyle , which was too high a price to pay . The generalized resistance caused the Soviet Union to abandon its original plan to oust the First Secretary . Dubček , who had been arrested on the night of 20 August , was taken to Moscow for negotiations . It was agreed that Dubček would remain in office , but he was no longer free to pursue to liberalization that he had before the invasion . On 19 January 1969 , student Jan Palach set himself on fire in Wenceslas Square in Prague to protest the renewed suppression of free speech . Finally , on 17 April 1969 , Dubček was replaced as First Secretary by Gustáv Husák , and a period of " Normalization " began . Pressure from the Soviet Union pushed politicians to either switch loyalties or simply give up . In fact , the very group that voted in Dubček and put the reforms in place were mostly the same people who annulled the program and replaced Dubček with Husák . Husák reversed Dubček ' s reforms , purged the party of its liberal members , and dismissed the professional and intellectual elites who openly expressed disagreement with the political turnaround from public offices and jobs . Reactions in other Warsaw Pact countries . Many people in the Soviet Union did not approve of the invasion . On 25 August , at the Red Square , eight protesters carried banners with anti - invasion slogans . The demonstrators were arrested and later punished , as the protest was dubbed " anti - Soviet " . In the People ' s Republic of Poland , on 8 September 1968 , Ryszard Siwiec immolated himself in Warsaw during a harvest festival at the 10th - Anniversary Stadium in protest against the Warsaw Pact ' s invasion of Czechoslovakia and the totalitarianism of the communist government . Siwiec did not survive . A more pronounced effect took place in the , which did not take part in the invasion . Nicolae Ceauşescu , already a staunch opponent of Soviet influences and one to have declared himself on Dubček ' s side , held a public speech in Bucharest on the day of the invasion , depicting Soviet policies in harsh terms . This response consolidated Romania ' s independent voice in the next two decades , especially after Ceauşescu encouraged the population to take up arms in order to meet any similar maneuver in the country : he received an enthusiastic initial response , with many people , who were by no means communist , willing to enroll in the newly formed paramilitary Patriotic Guards . In the German Democratic Republic , the invasion aroused discontent among those who had hoped that Czechoslovakia would pave the way for a more liberal socialism . However , isolated protests were quickly stopped by the police and Stasi . Albania responded in opposite fashion : already feuding with Moscow over suggestions that the country should focus on agriculture to the detriment of industrial development , and concerned that Moscow was becoming too liberal in its dealings with Yugoslavia ( which , by that time , Albania regarded as a threatening neighbor and had branded in propaganda as " imperialist " ) , it withdrew from the Warsaw Pact entirely . Economic fallout from this move was mitigated somewhat by a strengthening of Albanian relations with the People ' s Republic of China , which was itself on increasingly strained terms with the Soviet Union . In the fall of 1989 , Mikhail Gorbachev and other Warsaw Pact leaders drafted a statement calling the 1968 invasion a mistake . This acknowledgement likely helped to encourage the popular revolutions that overthrew communist governments in East Germany , Czechoslovakia , Poland , and Romania at the end of 1989 by providing assurance that no similar Soviet intervention would be repeated were such uprisings to occur . Reactions around the world . The night of the invasion , Canada , Denmark , France , Paraguay , the United Kingdom , and the United States all requested a meeting of the United Nations Security Council . That afternoon , the council met to hear the Czechoslovak Ambassador Jan Muzik denounce the invasion . Soviet Ambassador Jacob Malik insisted the Warsaw Pact actions were those of " fraternal assistance " against " antisocial forces . " The next day , several countries suggested a resolution condemning the intervention and calling for immediate withdrawal . US Ambassador George Ball , suggested that " the kind of fraternal assistance that the Soviet Union is according to Czechoslovakia is exactly the same kind that Cain gave to Abel . " Ball accused Soviet delegates of filibuster ing to put off the vote until the occupation was complete . Malik continued to speak , ranging in topics from US exploitation of Latin America ' s raw materials to statistics on Czech commodity trading . Eventually , a vote was taken . Ten members supported the motion ; Algeria , India , and Pakistan abstained ; the USSR ( with veto power ) and Hungary opposed it . Canadian delegates immediately introduced another motion asking for a UN representative to travel to Prague and work for the release of the imprisoned Czechoslovak leaders . Malik accused Western countries of hypocrisy , asking " who drowned the fields , villages , and cities of Vietnam in blood ? " By 26 August , another vote had not taken place , but a new Czechoslovak representative requested the whole issue be removed from the Security Council ' s agenda . Although the United States insisted at the UN that Warsaw Pact aggression was unjustifiable , its position was compromised by its own actions . Only three years earlier , US delegates to the UN had insisted that the overthrow of the leftist government of the Dominican Republic , as part of Operation Power Pack , was an issue to be worked out by the Organization of American States ( OAS ) without UN interference . The OAS accepted adherence to Marxism – Leninism as an armed attack justifying self - defense by the United States . American involvement in the Vietnam War led UN Secretary - General U Thant to draw further comparisons , suggesting that " if Russians were bombing and napalming the villages of Czechoslovakia " he might be more vocal in his denunciation . In effect , the western countries offered only vocal criticism following the invasion – the reality of the Cold War meant they were in no position to challenge Soviet military force in Central Europe without risking nuclear war . In Finland , a neutral country under some Soviet political influence at that time , the occupation caused a major scandal . Like the Italian and French Communist Parties , the Communist Party of Finland denounced the occupation . Nonetheless , Finnish president Urho Kekkonen was the very first Western politician to officially visit Czechoslovakia after August 1968 ; he received the highest Czechoslovakian honours from the hands of president Ludvík Svoboda on 4 October 1969 . The Portuguese communist secretary - general Álvaro Cunhal is believed to have been the only political leader from Western Europe to have supported the invasion for being counterrevolutionary , along with the Luxembourgian Communist Party . The United States government sent Shirley Temple Black , the famous child movie star , who became a diplomat in later life , to Prague in August 1968 to prepare to become the first United States Ambassador to a free Czechoslovakia . Two decades later , when Czechoslovakia became independent in 1989 , Mrs . Black was finally recognized as the first American ambassador to a truly free Czechoslovakia .