The document provides background information on the Cold War and the gradual thawing of relations between the US and USSR in the 1970s. It discusses key events like Nixon's visit to China in 1972, the first Strategic Arms Limitation Talks (SALT I) in the same year, and increasing efforts at détente between the two superpowers through diplomacy and arms control negotiations. However, tensions increased again in the late 1970s after the Soviet invasion of Afghanistan.