Détente

Détente, the relaxation of geopolitical tensions between the United States and the Soviet Union from the late 1960s to 1979, had a profound but ultimately transient impact on superpower relations. Driven by mutual exhaustion from the arms race, the economic burdens of the Cold War, and the sobering reality of Mutually Assured Destruction (MAD), both nations sought a more predictable international system. 

While détente successfully stabilized US-USSR relations in the short term through landmark arms control agreements and the diplomatic settlement of European borders, it ultimately failed to resolve the underlying ideological antagonism. Because the two superpowers held fundamentally divergent conceptions of what détente meant, their relations were increasingly undermined by proxy conflicts in the Third World, culminating in the complete collapse of the policy with the Soviet invasion of Afghanistan in December 1979. 

The Positive Impact: Stabilization and Arms Control

The most significant positive impact of détente was the institutionalization of nuclear parity, which dramatically reduced the immediate threat of nuclear war.

SALT I and the ABM Treaty (1972): The Strategic Arms Limitation Talks resulted in the Anti-Ballistic Missile Treaty, which restricted defensive systems, thereby cementing the doctrine of MAD. This was a paradigm shift; as historian John Lewis Gaddis argues, détente turned a highly volatile rivalry into a "managed" and predictable system.

The era saw unprecedented diplomatic engagement, notably the 1972 Moscow Summit and the signing of the "Basic Principles of Relations," which established a code of conduct aimed at preventing accidental conflicts. For a time, relations shifted from brinkmanship to pragmatic coexistence.

Détente also profoundly impacted relations by formally settling the post-WWII European landscape, which had been the primary theater of Cold War tension.

However, the agreement on offensive weapons was only an Interim Agreement designed to last for five years. It was a temporary stopgap meant to buy time for a more comprehensive treaty (SALT II), which proved incredibly difficult to negotiate and was ultimately never ratified by the US Senate.

SALT I created a false sense of security. The treaty relied on "National Technical Means" (spy satellites) for verification because the Soviets absolutely refused to allow on-site inspections, viewing them as espionage. While satellite verification worked for counting massive missile silos, it bred paranoia. Both sides constantly accused the other of bending the rules or exploiting loopholes, which eroded the very trust that détente was supposed to build.

SALT I placed a freeze on the number of launchers (ICBM silos and submarine tubes), but it placed absolutely no limits on the number of warheads that could be attached to a single missile. Consequently, while the number of missiles remained static, the number of actual nuclear warheads deployed by both sides skyrocketed during the 1970s.

Historian John Lewis Gaddis notes that by failing to ban MIRVs, SALT I essentially made the world more dangerous, as a single missile strike could now wipe out multiple targets, increasing the incentive for a preemptive "first strike."

The Helsinki Final Act (1975): The USSR achieved its long-standing goal of Western recognition of the post-WWII Soviet bloc borders (Basket I). In return, the US and its allies secured commitments to economic cooperation (Basket II) and human rights (Basket III).

Basket II

Signed by 35 nations (including the U.S. and USSR), Basket II focused entirely on cooperation in economics, science, technology, and environmental projects leading to increased industrial cooperation, expanded trade, and symbolic joint endeavors e.g.1975 Apollo-Soyuz Test Project, a high-profile joint space mission

Nixon and Kissinger believed that the Soviet Union desperately needed Western grain, technology, and capital to fix its stagnant economy thus the U.S. offered trade concessions and technology sharing as "carrots." to Manage Soviet behavior. The U.S. threatened to revoke these economic benefits if the Soviets acted aggressively in the Third World.

While Helsinki represented the high-water mark of diplomatic cooperation, it subtly shifted the nature of the conflict. The human rights provisions provided a legal framework for Soviet dissidents (like Andrei Sakharov) and Eastern European movements. Historians such as Raymond Garthoff note that while Helsinki stabilized borders, Basket III planted the seeds for the eventual internal decay of the Soviet bloc, creating a new avenue for US-USSR friction.

Was the Helsinki Final Act a Trojan Horse that destroyed the Soviet empire from within, or was it a massive Soviet geopolitical victory whose human rights impact has been retrospectively exaggerated?

Limitation of Détente

Détente did not end the Cold War because it did not align the strategic objectives of the two superpowers.

The impact of détente was severely limited by divergent expectations:

The Soviet Perspective: Under Brezhnev, the USSR viewed détente as an American acknowledgment of Soviet superpower parity. Crucially, the Soviets did not believe détente applied to the ideological struggle or the Third World; they felt entirely justified in supporting Marxist liberation movements.

The US Perspective: The Nixon-Kissinger strategy viewed détente as a way to manage Soviet power through "linkage"—offering economic benefits (like grain sales and technology) in exchange for Soviet restraint globally.

The US Congress actively undermined the executive branch's détente strategy. The Jackson-Vanik Amendment (1974) tied US-Soviet trade to the emigration rights of Soviet Jews, infuriating Moscow, who viewed it as an unacceptable interference in domestic affairs. This proved that domestic politics severely limited the diplomatic impact of détente.

The most glaring failure of détente was its inability to regulate superpower competition outside of Europe, which ultimately destroyed US-USSR relations by 1979.

The Middle East and Africa: The Yom Kippur War (1973) saw both superpowers heavily arming their respective clients, nearly resulting in a military confrontation. Furthermore, Soviet and Cuban intervention in the Angolan Civil War (1975) and the Ogaden War in the Horn of Africa (1977–1978) convinced Washington that the USSR was using détente as a smokescreen for expansionism.

Angola (1975): 

Following the collapse of Portuguese colonial rule in 1975, the Soviet Union and Cuba heavily backed the Marxist MPLA faction with weapons and troops during the Angolan Civil War

Mozambique (1975): 

Also gaining independence from Portugal in 1975, Mozambique established a Marxist-Leninist government under FRELIMO and immediately formed tight military and diplomatic ties with Moscow.

Ethiopia (1977–1978): 

The Soviet Union intervened heavily in the Ogaden War, airlifting massive amounts of military equipment and backing Cuban troops to support Ethiopia's Marxist Derg regime against Somalia

Afghanistan (December 1979): 

The absolute climax of this expansionist wave occurred when the Soviet military directly invaded Afghanistan to prop up a failing communist puppet government.

The Final Blow (1979): By 1979, relations were already deteriorating. Although Carter and Brezhnev signed SALT II in June 1979, the US Senate was highly skeptical. The Soviet invasion of Afghanistan in December 1979 was the definitive end of détente. Carter withdrew SALT II from the Senate, embargoed grain, and boycotted the 1980 Moscow Olympics. The invasion proved that the "Basic Principles" of 1972 had failed to restrain unilateral military action.

How did this affect the US-USSR relations?

This wave of Soviet expansion in the late 1970s completely shattered the era of détente and plunged US-USSR relations into a period of intense hostility often called the "Second Cold War.", shifting from peaceful coexistence back to aggressive proxy conflicts, the two superpowers rapidly destroyed a decade of diplomatic progress.

In his 1980 State of the Union address, President Carter declared that any attempt by an outside force to gain control of the Persian Gulf region would be repelled by military force.

The U.S. launched Operation Cyclone, a CIA program to secretly fund and arm the Afghan Mujahideen rebels fighting Soviet troops, turning Afghanistan into a bloody, decade-long proxy war for Moscow