When did the Soviet Union collapse?

The Soviet Union's collapse was not a single event but a process that accelerated over roughly two years, from the democratic revolutions of 1989 to the formal dissolution on December 26, 1991. The precise dates mark the stages of an empire's disintegration.

The dissolution process began in earnest with the revolutions of 1989 in Eastern Europe. Although the Eastern European states were formally independent, their loss stripped the Soviet Union of its buffer zone and demonstrated that communist systems could not survive without coercive force. Within the Soviet Union itself, nationalist movements in the Baltic states — Estonia, Latvia, and Lithuania — grew increasingly bold. Lithuania declared independence on March 11, 1990, becoming the first Soviet republic to do so.

Gorbachev attempted to preserve the Union through a new Union Treaty that would grant republics greater autonomy while maintaining a federal structure. But on August 19, 1991, Communist hardliners — alarmed by the treaty and by Gorbachev's reforms — launched a coup, placing Gorbachev under house arrest at his dacha in Crimea. The coup was poorly planned and quickly collapsed as Boris Yeltsin, president of the Russian Soviet Republic, rallied opposition from atop a tank outside the Russian parliament.

The failed coup destroyed what remained of central authority. In its aftermath, republic after republic declared independence: Ukraine (August 24), Belarus (August 25), Moldova (August 27), Azerbaijan (August 30), Kyrgyzstan (August 31), Uzbekistan (September 1), and others followed. On December 1, Ukraine's independence was confirmed by a referendum with over 90% approval — a decisive blow, as the Soviet Union without Ukraine was geographically and economically unviable.

On December 8, the leaders of Russia, Ukraine, and Belarus met at Belovezha Forest and declared the Soviet Union dissolved, replacing it with the Commonwealth of Independent States. On December 21, eleven former Soviet republics signed the Alma-Ata Protocol formalizing the CIS. On December 25, Gorbachev delivered his resignation speech. That evening, the Soviet hammer-and-sickle flag was lowered from the Kremlin and replaced by the Russian tricolor. On December 26, the Soviet of the Republics formally voted the Soviet Union out of existence.

The dissolution of the Soviet Union — a nuclear-armed superpower encompassing eleven time zones and nearly 300 million people — was accomplished without a major armed conflict between the center and the republics. This remarkably peaceful ending, largely attributable to Gorbachev's refusal to use overwhelming force, was one of the most extraordinary events of the 20th century.