In August 1991, hardliners of the Communist Party of the Soviet Union (CPSU) attempted to forcibly seize control of the country from Mikhail Gorbachev, who was Soviet president and General Secretary of the CPSU at the time. The coup leaders consisted of top military and civilian officials, including Vice President Gennady Yanayev, who together formed the State Committee on the State of Emergency (Russian: ГКЧП, romanized: GKChP). Opposed to Gorbachev's reform program, they were angry at the loss of control over Eastern European states and fearful of the New Union Treaty, which was on the verge of being signed by the Soviet Union (USSR). The treaty was to decentralize much of the central Soviet government's power and distribute it among its fifteen republics. Boris Yeltsin's demand for more autonomy to the republics opened a window for the plotters to organize the coup. The attempt took place between 19 and 21 August 1991; as a result, the events were referred to as the August Coup.
The GKChP hardliners dispatched KGB agents who detained Gorbachev at his dacha but failed to detain the recently elected president of Russia, Boris Yeltsin, who had been both an ally and critic of Gorbachev. The GKChP was poorly organized and met with effective resistance by both Yeltsin and a civilian campaign of anti-authoritarian protesters, mainly in Moscow. The coup collapsed in two days, and Gorbachev returned to office while the plotters all lost their posts. Yeltsin subsequently became the dominant leader and Gorbachev lost much of his influence. The failed coup led to both the immediate collapse of the CPSU and the dissolution of the USSR four months later.
Following the capitulation of the GKChP, popularly referred to as the "Gang of Eight", both the Supreme Court of the Russian Soviet Federative Socialist Republic (RSFSR) and President Gorbachev described its actions as a coup attempt.
Since assuming power as General Secretary of the Communist Party of the Soviet Union in 1985, Gorbachev had embarked on an ambitious reform program embodied in the twin concepts of perestroika (economic and political restructuring) and glasnost (openness). These moves prompted resistance and suspicion on the part of hard-line members of the nomenklatura. The reforms also caused nationalist agitation on the part of the Soviet Union's non-Russian minorities to grow, and there were fears that some or all of the union republics might secede. In 1991, the Soviet Union was in a severe economic and political crisis. Scarcity of food, medicine, and other consumables was widespread, people had to stand in long lines to buy even essential goods, fuel stocks were as much as 50% lower than the estimated amount needed for the approaching winter, and inflation exceeded 300% per year, with factories lacking the cash needed to pay salaries.
In 1990, Estonia, Latvia, Lithuania and Armenia had already declared the restoration of their independence from the Soviet Union. In January 1991, a violent attempt to return Lithuania to the Soviet Union by force took place. About a week later, a similar attempt was engineered by local pro-Soviet forces to overthrow Latvian authorities. These attempts failed, and Lithuania and Latvia retained their statehood.
Russia declared its sovereignty on 12 June 1990 and thereafter limited the application of Soviet laws, in particular those governing finance and the economy, on Russian territory. The Supreme Soviet of the Russian SFSR adopted laws that contradicted Soviet laws (the so-called War of Laws).
In the unionwide referendum on 17 March 1991, boycotted by the Baltic states, Armenia, Georgia, and Moldova, a supermajority of residents in the other republics expressed the desire to retain the renewed Soviet Union, with 77.85% voting in favor. Following negotiations, eight of the remaining nine republics (Ukraine abstaining) approved the New Union Treaty with some conditions. The treaty was to make the Soviet Union a federation of independent republics called the Union of Soviet Sovereign Republics, with a common president, foreign policy, and military. Russia, Kazakhstan and Uzbekistan were to sign the Treaty in Moscow on 20 August 1991.
British historian Dan Stone wrote the following about the plotters' motivation: The coup was the last gasp of those who were astonished at and felt betrayed by the precipitous collapse of the Soviet Union's empire in Eastern Europe and the swift destruction of the Warsaw Pact and Comecon that followed. Many feared the consequences of Gorbachev's German policies above all, not just for leaving officers unemployed but for sacrificing gains achieved in the Great Patriotic War to German revanchism and irredentism – after all, this had been the Kremlin's greatest fear since the end of the war.
The KGB began considering a coup in September 1990. Soviet politician Alexander Yakovlev began warning Gorbachev about the possibility of one after the 28th Party Congress in June 1990. On 11 December 1990, KGB Chairman Vladimir Kryuchkov made a "call for order" over the Moscow Programme television station. That day, he asked two KGB officers to prepare measures to be taken in the event a state of emergency was declared in the USSR. Later, Kryuchkov brought Soviet Defense Minister Dmitry Yazov, Central Control Commission Chairman Boris Pugo, Premier Valentin Pavlov, Vice President Gennady Yanayev, Soviet Defense Council deputy chief Oleg Baklanov, Gorbachev secretariat head Valery Boldin, and CPSU Central Committee Secretary Oleg Shenin into the conspiracy.
When Kryuchkov complained about the Soviet Union's growing instability to the Congress of People's Deputies, Gorbachev attempted to appease him by issuing a presidential decree enhancing the powers of the KGB and appointing Pugo to the Cabinet as Minister of Internal Affairs. Foreign Secretary Eduard Shevardnadze resigned in protest and rejected an offered appointment as vice president, warning that "a dictatorship is coming." Gorbachev was forced to appoint Yanayev in his place.
Beginning with the January Events in Lithuania, members of Gorbachev's Cabinet hoped that he could be persuaded to declare a state of emergency and "restore order," and formed the State Committee on the State of Emergency (GKChP).
On 17 June 1991, Soviet premier Pavlov requested extraordinary powers from the Supreme Soviet. Several days later, Moscow Mayor Gavriil Popov informed U.S. ambassador to the Soviet Union Jack F. Matlock Jr. that a coup against Gorbachev was being planned. When Matlock tried to warn him, Gorbachev falsely assumed that his own Cabinet was not involved and underestimated the risk of a coup. Gorbachev reversed Pavlov's request for more powers and jokingly told his Cabinet "The coup is over," remaining oblivious to their plans.
On 23 July 1991, several party functionaries and literati published a piece in the hardline Sovetskaya Rossiya newspaper, entitled "A Word to the People", that called for decisive action to prevent calamity.
Six days later, on 29 July, Gorbachev, Russian president Boris Yeltsin and Kazakh president Nursultan Nazarbayev discussed the possibility of replacing hardliners such as Pavlov, Yazov, Kryuchkov and Pugo with more liberal figures, with Nazarbayev as Prime Minister (in Pavlov's place). Kryuchkov, who had placed Gorbachev under close surveillance as Subject 110 several months earlier, eventually got wind of the conversation from an electronic bug planted by Gorbachev's bodyguard, Vladimir Medvedev. Yeltsin also prepared for a coup by establishing a secret defense committee, ordering military and KGB commands to side with RSFSR authorities and establishing a "reserve government" about 70 kilometers from Sverdlovsk under Deputy Prime Minister Oleg Lobov.
On 4 August, Gorbachev went on holiday to his dacha in Foros, Crimea. He planned to return to Moscow in time for the New Union Treaty signing on 20 August. On 15 August, the text of the draft treaty was published, which would have stripped the coup planners of much of their authority.