In the early 1970s, there was a brief détente of relations with the United States, but tensions resumed with the Soviet–Afghan War in 1979. In 1985, the last Soviet premier, Mikhail Gorbachev, sought to reform and liberalize the economy through his policies of glasnost (openness) and perestroika (restructuring), which caused political instability. In 1989, Soviet satellite states in Eastern Europe overthrew their respective communist governments.