The Intermediate-Range Nuclear Forces Treaty (INF Treaty) was an arms control treaty between the United States and the Soviet Union (and its successor state, the Russian Federation). US president Ronald Reagan and Soviet General Secretary Mikhail Gorbachev signed the treaty on 8 December 1987. The US Senate approved the treaty on 27 May 1988, and Reagan and Gorbachev ratified it on 1 June 1988.
The INF Treaty banned all of the two nations' nuclear and conventional ground-launched ballistic missiles, cruise missiles, and missile launchers with ranges of 1,000–5,500 km (620–3,420 mi) ("intermediate-range") and 500–1,000 kilometers (310–620 mi) ("shorter-range"). The treaty did not apply to air- or sea-launched missiles. By May 1991, the nations had eliminated 2,692 missiles, followed by 10 years of on-site verification inspections.
President Donald Trump announced on 20 October 2018 that he was withdrawing the US from the treaty due to Russian non-compliance, claiming that Russia had breached the treaty by developing and deploying an intermediate-range cruise missile known as the SSC-8 (Novator 9M729). The Trump administration claimed another reason for the withdrawal was to counter a Chinese arms buildup in the Pacific, including within the South China Sea, as China was not a signatory to the treaty. The US formally suspended the treaty on 1 February 2019, and Russia did so on the following day in response. The United States formally withdrew from the treaty on 2 August 2019. Russia announced it will no longer abide by the treaty on 4 August 2025.
In March 1976, the Soviet Union first deployed the RSD-10 Pioneer (called SS-20 Saber in the West) in its European territories; it was a mobile, concealable intermediate-range ballistic missile (IRBM) with a multiple independently targetable reentry vehicle (MIRV) containing three nuclear 150-kiloton warheads. The SS-20's range of 4,700–5,000 kilometers (2,900–3,100 mi) was long enough to reach Western Europe from well within Soviet territory; it was just below the Strategic Arms Limitation Talks II (SALT II) Treaty minimum range for an intercontinental ballistic missile (ICBM), 5,500 km (3,400 mi). The SS-20 replaced the aging SS-4 Sandal and SS-5 Skean, which were seen to pose a limited threat to Western Europe due to their poor accuracy, limited payload (one warhead), lengthy time to prepare to launch, difficulty of concealment, and a lack of mobility that exposed them to pre-emptive NATO strikes ahead of a planned attack. While the SS-4 and SS-5 were seen as defensive weapons, the SS-20 was seen as a potentially offensive system.
The United States, then under President Jimmy Carter, initially considered its strategic nuclear weapons and nuclear-capable aircraft to be adequate counters to the SS-20 and a sufficient deterrent against possible Soviet aggression. In 1977, however, Chancellor Helmut Schmidt of West Germany argued in a speech that a Western response to the SS-20 deployment should be explored, a call which was echoed by NATO, given a perceived Western disadvantage in European nuclear forces. Leslie H. Gelb, the US Assistant Secretary of State, later recounted that Schmidt's speech pressured the US into developing a response.
On 12 December 1979, following European pressure for a response to the SS-20, Western foreign and defense ministers meeting in Brussels made the NATO Double-Track Decision. The ministers argued that the Warsaw Pact had "developed a large and growing capability in nuclear systems that directly threaten Western Europe": "theater" nuclear systems (i.e., tactical nuclear weapons). In describing this aggravated situation, the ministers made direct reference to the SS-20 featuring "significant improvements over previous systems in providing greater accuracy, more mobility, and greater range, as well as having multiple warheads". The ministers also attributed the altered situation to the deployment of the Soviet Tupolev Tu-22M strategic bomber, which they believed had much greater performance than its predecessors. Furthermore, the ministers expressed concern that the Soviet Union had gained an advantage over NATO in "Long-Range Theater Nuclear Forces" (LRTNF), and also significantly increased short-range theater nuclear capacity.
The Double-Track Decision involved two policy "tracks". Initially, 1,000 of the 7,400 theater nuclear warheads would be removed from Europe, and the US would pursue bilateral negotiations with the Soviet Union, intended to limit theater nuclear forces. Should these negotiations fail, NATO would modernize its own LRTNF, or intermediate-range nuclear forces (INF), by replacing US Pershing 1a missiles with 108 Pershing II launchers in West Germany and deploying 464 BGM-109G Ground Launched Cruise Missiles (GLCMs) to Belgium, Italy, the Netherlands, and the United Kingdom beginning in December 1983.
The Soviet Union and United States agreed to open negotiations and preliminary discussions, named the Preliminary Intermediate-Range Nuclear Forces Talks, which began in Geneva, Switzerland, in October 1980. The relations were strained at the time due to the 1979 Soviet invasion of Afghanistan which led America to impose sanctions against the USSR. On 20 January 1981, Ronald Reagan was sworn into office after defeating Jimmy Carter in the 1980 United States presidential election. Formal talks began on 30 November 1981, with the US negotiators led by Reagan and those of the Soviet Union by General Secretary, Leonid Brezhnev. The core of the US negotiating position reflected the principles put forth under Carter: any limits placed on US INF capabilities, both in terms of "ceilings" and "rights", must be reciprocated with limits on Soviet systems. Additionally, the US insisted that a sufficient verification regime be put in place.
Paul Nitze, an experienced politician and long-time presidential advisor on defense policy who had participated in the SALT talks, led the US delegation after being recruited by Secretary of State Alexander Haig. Though Nitze had backed the first SALT treaty, he opposed SALT II and had resigned from the US delegation during its negotiation. Nitze was also then a member of the Committee on the Present Danger, a firmly anti-Soviet group composed of conservative Republicans. Yuli Kvitsinsky, the second-ranking official at the Soviet embassy in West Germany, headed the Soviet delegation.
On 18 November 1981, shortly before the beginning of formal talks, Reagan made the Zero Option or "zero-zero" proposal. It called for a hold on US deployment of GLCM and Pershing II systems, reciprocated by Soviet elimination of its SS-4, SS-5, and SS-20 missiles. There appeared to be little chance of the Zero Option being adopted due to Soviet opposition, but the gesture was well received by the European public. In February 1982, US negotiators put forth a draft treaty containing the Zero Option and a global prohibition on intermediate- and short-range missiles, with compliance ensured via a stringent, though unspecified, verification program.
Opinion within the Reagan administration on the Zero Option was mixed. Richard Perle, then the Assistant Secretary of Defense for Global Strategic Affairs, was the architect of the plan. Secretary of Defense Caspar Weinberger, who supported a continued US nuclear presence in Europe, was skeptical of the plan, though eventually accepted it for its value in putting the Soviet Union "on the defensive in the European propaganda war". Reagan later recounted that the "zero option sprang out of the realities of nuclear politics in Western Europe". The Soviet Union rejected the plan shortly after the US tabled it in February 1982, arguing that both the US and USSR should be able to retain intermediate-range missiles in Europe. Specifically, Soviet negotiators proposed that the number of INF missiles and aircraft deployed in Europe by each side be capped at 600 by 1985 and 300 by 1990. Concerned that this proposal would force the US to withdraw aircraft from Europe and not deploy INF missiles, given US cooperation with existing British and French deployments, the US proposed "equal rights and limits"—the US would be permitted to match Soviet SS-20 deployments.