Last night, stinger asked for more information on the causes of the breakup of the Soviet Union. Here’s a short summary of my understanding, with some references, not all (sorry!) links.
The Soviet economic system was faltering from the sixties on. The First Secretaries during that period were slow-moving, sick, and in no way capable of innovating out of that situation. It may have been inherently impossible in any case. Manufacturing of anything but weapons never was a significant part of the economy, which depended on oil exports.
The Soviet Union was made up of 15 Union republics. Some of those republics became part of the Soviet Union after World War II but had fought civil wars for independence from the Russian empire during and after the Russian Revolution in 1917. The Baltic States in particular, but other republics as well, were not happy members of the Union. Moscow went through waves of Russification, in which the Russian language was forced on populations for which it was not native. Social restrictions sometimes accompanied the language crackdowns.
Most of the rest of the world refused to recognize the Baltic republics as part of the Soviet Union. Token embassies were maintained in Washington and London.
By the 1980s, even the Soviets were beginning to realize they had a problem. The arms race with the United States had been partly tamed by the SALT arms control agreements, but an intermediate-missile race was burning. Building armaments was bleeding money and industrial capacity out of the economy. Mikhail Gorbachev, a newcomer with promise, was made First Secretary in March 1985.