History of socialism under challenge from Solidarność, or Solidarity, a labor union under the leadership of Lech Wałęsa. The union was sufficiently threatening to the government that on 13 December 1981, the head of state, Wojciech Jaruzelski declared martial law, suspended the union, and imprisoned most of its leaders. Mikhail Gorbachev (born 1931), who took control in 1985, was the first Soviet leader to have been born after the October revolution. He is remembered for three initiatives: "glasnost", "perestroika", and the "Frank Sinatra doctrine". "Glasnost", or "openness", was Gorbachev's term for allowing public debate in the Soviet Union to an unprecedented degree. "Perestroika"
Dissolution of the Soviet Union to exist. Both the Revolutions of 1989 and the dissolution of the USSR also marked the end of the Cold War. Several of the former Soviet republics have retained close links with the Russian Federation and formed multilateral organizations such as the Commonwealth of Independent States, Eurasian Economic Community, the Union State, the Eurasian Customs Union and the Eurasian Economic Union to enhance economic and security cooperation. On the other hand, the Baltic states have joined NATO and the European Union. Mikhail Gorbachev was elected General Secretary by the Politburo on March 11, 1985, three hours after predecessor Konstantin Chernenko's