In Europe, the Ostpolitik of Willy Brandt was decreasing tensions; the Soviets hoped that with Détente, more trade with Western Europe would be possible. Soviet thinkers also felt that a less aggressive policy could potentially detach the Western Europeans from their American WRC.
Worsening relations with the People's Republic of China, leading to the Sino-Soviet Split, had caused great concern in the Soviet Union. The leadership feared the potential of a Sino-American alliance against them and believed it necessary to improve relations with the United States. Improved relations with China had already thawed the general American view of communism.
Rough parity had been achieved in stockpiling nuclear weapons with a clear capability of mutually assured destruction (MAD). There was also the realization that the "relative gains" theory as to the predictable consequences of war might no longer be appropriate. A "sensible middle ground" was the goal.
Brezhnev and Nixon each hoped improved relations would boost their domestic popularity and secure their power.
Several anti-nuclear movements supported détente. The Cuban missile crisis showed how dangerous the relations between the USSR and the USA were becoming. Kennedy and Khruchshev wished to reduce the risk of a nuclear war, as they were aware that the nuclear arsenals on each side granted mutually assured destruction.
The most important treaties were not developed until the advent of the Nixon Administration, which came into office in 1969. The Political Consultative Committee of the Warsaw Pact sent an offer to the West, urging to hold a summit on "security and cooperation in Europe". The West agreed and talks began towards actual limits in the nuclear capabilities of the two superpowers. This ultimately led to the signing of the SALT I treaty in 1972. This treaty limited each power's nuclear arsenals, though it was quickly rendered out-of-date as a result of the development of MIRVs. In the same year that SALT I was signed, the Biological Weapons Convention and the Anti-Ballistic Missile Treaty were also concluded. Talks on SALT II also began in 1972.
In 1975, the Conference on Security and Cooperation in Europe met and produced the Helsinki Accords, a wide ranging series of agreements on economic, political, and human rights issues. The CSCE was initiated by the USSR, involving thirty-five states throughout Europe. Amongst other issues, one of the most prevalent and discussed after the conference was that of human rights violations in the Soviet Union. The Soviet Constitution directly violated the Declaration of Human Rights from the United Nations, and this issue became a prominent point of separation between the United States and the Soviet Union. The Carter administration had been supporting human rights groups inside the Soviet Union, and Brezhnev accused the administration of interference in other countries’ internal affairs. This prompted intense discussion of whether or not other nations may interfere if basic human rights are being violated, such as freedom of speech and religion. The basic disagreement in the philosophies of a democracy and a single-party state did not allow for reconciliation of this issue. Furthermore, the Soviets proceeded to defend their internal policies on human rights with attacking American support of countries like South Africa and Chile which were known to violate many of the same human rights issues.
In July of the same year, the Apollo-Soyuz Test Project became the first international space mission, with three American astronauts and two Russian cosmonauts docking their spacecraft and conducting joint experiments. This mission had been preceded by five years of political negotiation and technical co-operation, including exchanges of US and Russian engineers between the two countries' space centers.
Trade relations between the two blocs increased substantially during the era of détente. Most significant were the vast shipments of grain that were sent from the West to the Soviet Union each year, which helped make up for the failure of kolkhoz, Soviet collectivized agriculture.
At the same time, the Jackson-Vanik amendment, signed into law by Gerald Ford on January 3, 1975, after a unanimous vote by both houses of the United States Congress, was designed to leverage trade relations between the U.S. and the USSR, making them dependent upon improvements of human rights within the Soviet Union, in particular allowing refusniks to emigrate.
The main problem with détente is that there was no clear definition of how friendly and co-operative these two nations were to become. Some historians and politicians have argued that this lack of clarity in the détente relationship was mainly to blame for the collapse of American-Soviet relations at the end of the 1970s. Mike Bowker and Phil Williams addressed this problem as the minimalist versus the maximalist approach in Superpower Détente: A Reappraisal. The minimalist approach simply recognizes the difference between two adversaries, and calls for a lack of tension. The maximalist approach goes further in active pursuit of a mutually beneficial, almost friendly, relationship between two nations.Bowker and Williams raise the issue of conflicting understanding between Moscow and Washington; even if both administrations followed the maximalist approach, there may have been different interpretations of what was acceptable from the beginning of détente and what the desired outcomes would be.
Détente began to unravel in 1979. The Iranian Revolution and the subsequent hostage crisis embarrassed the United States and led much of the American public to believe their nation had lost its international power and prestige.
The Soviet invasion of Afghanistan that was to shore up a struggling allied regime led to harsh criticisms in the west and a boycott of the 1980 Summer Olympics, which were to be held in Moscow. American President Jimmy Carter boosted the U.S. defense budget and began financially aiding the President of Pakistan General Muhammad Zia-ul-Haq heavily, who would in turn subsidize the anti-Soviet Mujahideen fighters in the region.