Dissolution of the Soviet Union: The August Coup begins when Soviet President Mikhail Gorbachev is placed under house arrest while on holiday in the town of Foros, Ukraine.

The Soviet Union was formally dissolved as a sovereign state and subject of international law on 26 December 1991 by Declaration No. 142-N of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. It also brought an end to the Soviet Union's federal government and General Secretary Mikhail Gorbachev's effort to reform the Soviet political and economic system in an attempt to stop a period of political stalemate and economic backslide. The Soviet Union had experienced internal stagnation and ethnic separatism. Although highly centralized until its final years, the country was made up of 15 top-level republics that served as the homelands for different ethnicities. By late 1991, amid a catastrophic political crisis, with several republics already departing the Union and Gorbachev continuing the waning of centralized power, the leaders of three of its founding members, the Russian, Belorussian, and Ukrainian SSRs, declared that the Soviet Union no longer existed. Eight more republics joined their declaration shortly thereafter. Gorbachev resigned on 25 December 1991 and what was left of the Soviet parliament voted to dissolve the union the following day.

The 1991 Soviet coup attempt, also known as the August Coup, was a failed attempt by hardliners of the Communist Party of the Soviet Union (CPSU) 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. They opposed Gorbachev's reform program, 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 president of the Soviet Union, officially the president of the Union of Soviet Socialist Republics, abbreviated as president of the USSR, was the executive head of state of the Union of Soviet Socialist Republics from 15 March 1990 to 25 December 1991.