Why did relations between the Soviet Union and the USA change in the years 1970-1985?

* The 1979 soviet invasion of Afghanistan.* The Zero Option* Deployment of missiles in Europe* Strategic Defence opening moveBetween the years 1979 1985, transaction among the Soviet Union and the USA, changed, and we can look at galore(postnominal) reasons as to why this was the case.For example up until 1979, the superpowers were in a layover of Detente. Detente was simply a period of extended Co-operation and agreement. So relations had slightly improved up until 1979. Sadly this improvement of relations came to a Holt, as the Soviet Union invaded Afghanistan. The Soviets saw Fundamentalism as a great threat to the soviet system, and so the PDPA who were a communist party overthrew Afghan government. Before the invasion, Afghanistan seeked to improve relations with the USA, so by trespassing(a) Afghanistan this would moderate, perhaps annoyed the USA.The USA however did heavily criticise the invasion, which only put more argumentation on relations. The way, in which the US A showed their annoyance and disapproval of the War, was to boycott the1980 Moscow Olympic Games. In say to the USA boycott the Soviet Union were not present at the 1984 Los Angeles games. Clearly unrest in the midst of both Super Powers was emerging, and they showed this by their boycott of each Olympic Games. Had the Soviets not invaded Afghanistan you wonder whether the USA would have boycotted the games.In 1981 Ronald Reagan was elected president. By him becoming president, it only worsened things, as he was very corroboratory of anti Communist forces in places such as Afghanistan. Reagan also proposed the postcode option. This was basically the deployment of new US intermediate range missiles in Western Europe in return for soviet dismantlement of comparable with(predicate) forces. There are some Historians who think Reagan knew that Brezhnev would refuse, which meant he could therefore build bigger and greater weapons. This zero option only helped contribute to worsened relations a great deal, and by the Soviet rejecting zero option it gave Reagan the opportunity to accuse the Soviet Union of being an evil empire, but Yuri Andropov responded and called Reagan insane and a liar. Relations were direct at a low, and it seems there is no co-operation, but accusations instead.The Strategic Defence Initiative (SDI) commonly called wiz Wars. It was proposed by U.S. President Ronald Reagan on March 23, 1983 to use ground-based and space-based systems to protect the United States from attack by strategic thermonuclear ballistic missiles. The aim of SDI was to create a defence shield that would protect the USA from a fully nuclear missile attack by the Soviet Union or different hostile nuclear powers. This would end reliance on offence-dominated deterrence (Mutually Assured Destruction) through a balance of terror. Diplomatically, Russia and ferociously opposed SDI, and the deployment of such a system would have been a breach of the 1972 Anti-Ballistic Missiles (ABM) treaty. This also meant that USA had through something which the Soviets were opposed to, which can only have also worsened relations.The ongoing worsened relations were not helped by the fact that throughout 1979-1985 there was no stability in the Soviet Union. Leaders unploughed changing meaning the Super Powers did not have the time to relate to each other and rile an effort to improve relations. Say the minute a attraction came in, and they actually agreed on something, then, that leader would die, and they would have to start again.On overall, all of the factors I have mentioned above all contribute to a worsening of relations between the Soviet Union and the USA. It seems that each thing happens one after the other and they are not positives steps. When Brezhnev was in charge, the war in Afghanistan was going on, and after his death, you might expect relations to improve, but then Reagan announces zero option and so on. So between the years 1979-1980 it seem s that relations worsened, and the levels of trust between the USA and the Soviet Union worsened.