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Soviet-Afghan war:
The Soviet intervention in Afghanistan in 1979 cooled relations between the two superpowers and put an end to the period of détente that had started in the 1960s. It was a direct military intervention by one of them in a regional conflict, not a war fought by a proxy. It elicited an American reaction which was the formation, training and support of an anti-Soviet guerrilla made up of local Islamic fighters, the Mujahedeen. Afghanistan was a neighbor of Pakistan - an American ally - and it bordered the Soviet Union.
Iran-Contra affair:
Given the refusal of the US Congress to continue to finance the Contras who fought against the leftist, Soviet-friendly, Cuban-supported Sandinista regime in Nicaragua, some Ronald Reagan administration officers looked for ways to get financing, some of them were not legal. The affair didn´t have a major impact on the overall state of US-Soviet relations, because the main tensions were in Europe. Besides, those were the years of dialogue and negotiations with Soviet leader Mikhail Gorbachev. Reagan and Gorbachev held some summits and signed a treaty aimed at reducing some types of nuclear weapons. Nicaragua was never a strategic concern for the Soviets, despite deep Cuban involvement.
Iran got weapons for its 8-year war with the Iraqi regime of Saddam Hussein. Some reports suggested the release of American hostages kidnapped by militias related to Iran in the Middle East was achieved as an exchange for weapons, but the US government denied it.
For Nicaragua, it meant the continuation of the war between the Sandinista army and the Contra guerrillas based in Honduras. The US administration kept supporting them. The war seriously harmed the Nicaraguan economy and put much pressure on the Sandinista revolution and society.
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