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"
Mikhail Gorbachev major campaign to limit alcohol consumption, which Gorbachev—who believed it would improve health and work efficiency—oversaw. His wife keenly supported the measure. As a result, crime rates fell and life expectancy grew slightly between 1986 and 1987. The reform had significant costs to the Soviet economy, resulting in losses of up to $100 billion between 1985 and 1990. Gorbachev later considered the campaign to have been an error. In April 1986 the Chernobyl disaster occurred; in the immediate aftermath, officials fed Gorbachev incorrect information to downplay the incident. As the scale of the disaster became apparent, 336,000 people were evacuated