The inauguration of Ronald Reagan in 1981 meant a renewed support for right-wing authoritarian regimes in Latin America. In the 1980s, the situation progressively evolved in the world as in South America, despite a renewal of the Cold War from 1979 to 1985, the year during which Mikhail Gorbachev replaced Konstantin Chernenko as leader of the USSR, and began to implement the glasnost and the perestroika democratic-inspired reforms. South America saw various states returning progressively to democracy. This democratization of South America found a symbol in the OAS' adoption of Resolution 1080 in 1991, which requires the Secretary General to convene the Permanent Council within ten days of a coup d'état in any member country. However, at the same time, Washington started to aggressively pursue the "War on Drugs", which included the invasion of Panama in 1989 to overthrow Manuel Noriega, who had been a long-time ally of the US and had even worked for the CIA before his reign as leader of the country. The "War on Drugs" was later expanded through Plan Colombia in the late 1990s and the Mérida Initiative in Mexico and Central America.