START I

• 1. Introduction

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  START I, the Strategic Arms Reduction Treaty, was signed on the 31st of July 1991 by the leaders of two nations that had spent four decades pointing tens of thousands of nuclear warheads at each other. When its final implementation concluded in late 2001, roughly 80 percent of all strategic nuclear weapons then in existence had been removed. That scale of reduction had never been attempted before in any arms control agreement in history. What made this treaty possible, and what nearly stopped it? How do you verify that a rival superpower has actually destroyed its most dangerous weapons? And what happens to a treaty between two countries when one of those countries ceases to exist?

• 2. Reagan's Opening Bid

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  On the 9th of May 1982, Ronald Reagan stood before graduating students at Eureka College, his alma mater, and announced a sweeping proposal to cut strategic nuclear forces. Within weeks, he formally presented the plan in Geneva on the 29th of June 1982. Reagan called it SALT III at first, framing it as a successor to earlier arms negotiations. It would later be renamed START.

  The proposal was organized in two phases. In the first phase, the total number of warheads on any missile type would be capped at 5,000, with a further sub-limit of 2,500 on ICBMs. No more than 850 ICBMs would be allowed in total, with only 110 permitted to be "heavy throw" missiles of the kind represented by the Soviet SS-18. The second phase would add equivalent limits on bombers and their weapons.

  Critics noticed immediately that the proposed limits would press harder on the Soviets than on the United States. At the time, the Soviet Union held a nearly 3-to-1 advantage over the US in missile throw weight, the cumulative capacity to hurl warheads at a target. A uniform warhead cap, regardless of how it looked on paper, would therefore require the Soviets to make far deeper cuts. Time magazine wrote that the proposal was "a deceptively equal-looking, deliberately nonnegotiable proposal," and speculated that it might represent a hardliner strategy of sabotaging disarmament to allow the US to focus on rearmament.

  Soviet air power also factored into Reagan's calculations. Of the roughly 1,200 medium and heavy bombers in the Soviet fleet, only about 150 could reach North American soil, and even those, the Myasishchev M-4s, required in-flight refueling. That asymmetry shifted in 1984, when new Tu-95MS and Tu-160 bombers entered Soviet service equipped with the first Soviet AS-15 cruise missiles. The US, meanwhile, was quietly developing what would eventually become the B-2 Spirit stealth bomber.

• 3. A Decade of Negotiations

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  Formal negotiations for START began in May 1982, but the process repeatedly stalled. Pre-Gorbachev Soviet leadership regarded US terms as nonnegotiable, and in November 1983 the Soviet Union cut off communication with Washington after the US deployed intermediate-range missiles in Europe.

  The logjam began to ease in January 1985, when Secretary of State George Shultz and Soviet Foreign Minister Andrei Gromyko agreed to a framework for three-part talks covering strategic weapons, intermediate missiles, and missile defense. The real turning point came at the Reykjavik Summit in October 1986, where Reagan and Gorbachev personally accelerated the process. Reagan's Strategic Defense Initiative, announced in 1983, had alarmed Moscow and complicated earlier talks. The signing of the Intermediate-Range Nuclear Forces Treaty in December 1987 cleared space for the larger strategic agreement to follow.

  Throughout the 1980s, a dramatic nuclear arms race continued in parallel with the negotiations. It ended in 1991 with both sides holding roughly 10,000 strategic warheads, a rough parity that framed the final terms of the agreement. The treaty was ultimately signed not by Reagan, who had proposed it, but by President George H. W. Bush and Soviet General Secretary Mikhail Gorbachev on the 31st of July 1991.

• 4. Watching Each Other

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  The START verification regime was, at the time of signing, the most complicated and demanding of any arms control agreement ever concluded. It provided for twelve different types of inspection, a number that reflected hard-won experience with Soviet noncompliance concerns and American wariness of espionage.

  Parties were required to exchange data on the exact quantities, technical characteristics, locations, movements, and status of every offensive nuclear system. A provision known as national technical means of verification protected satellites and other remote sensing tools that each side used to monitor compliance. A companion provision protected multilateral technical systems referenced in other treaties. Cooperative measures required that weapons systems be displayed openly, not concealed from detection.

  On-site inspections and Perimeter and Portal Continuous Monitoring, known as PPCM, stationed representatives from the verifying side continuously at monitored facilities. Both parties also had to exchange telemetry recordings from ballistic missile flight tests and were prohibited from encrypting or encapsulating that data.

  The US Senate had specific concerns about the risks of verification. Senators worried Russia might covertly produce additional missiles, submit false warhead counts, or use inspection access to conduct espionage at US bases. The Joint Chiefs of Staff assessed both risks as falling within acceptable limits, a conclusion that helped secure Senate support. A compliance incident did emerge in 1994, when Arms Control and Disarmament Agency Director John Holum testified before Congress that Russia had converted its SS-19 ICBM into a space-launch vehicle without filing the required notifications. Russia argued the reporting obligations did not apply to missiles repurposed in this way. The dispute was resolved in 1995.

• 5. The Cost of Disarmament

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  Three separate institutions estimated what START I would actually cost the United States to implement, and their answers varied significantly. The Congressional Budget Office put the one-time implementation cost at between $410 million and $1,830 million, with continuing annual costs of $100 million to $390 million. The Senate Foreign Relations Committee estimated one-time costs of $200 million to $1,000 million, and projected total inspection expenses over the treaty's fifteen years at $1,250 million to $2,050 million. The Institute for Defense Analyses focused solely on verification, placing that figure at around $760 million.

  On top of those direct costs, the United States funded the Cooperative Threat Reduction Program, also known as the Nunn-Lugar Program, which channeled $591 million toward securing and dismantling nuclear materials in the former Soviet republics. That contribution nearly doubled the overall US cost of the START program in the former Soviet Union.

  The argument for absorbing those costs rested on projected savings. The Congressional Budget Office estimated that the US would save $46 billion in the first five years alone, and approximately $130 billion through 2010, by avoiding the expense of maintaining and upgrading nuclear forces that the treaty would eliminate. That projected savings figure was roughly twenty times the estimated cost of implementation. After the Soviet Union's arsenal was reduced under the treaty, the former Soviet stock fell from approximately 12,000 warheads to 3,500.

• 6. Destroying the Bombers

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  375 B-52 bombers were flown to the Aerospace Maintenance and Regeneration Center at Davis-Monthan Air Force Base in Arizona to be destroyed. Each aircraft was sliced apart by a 13,000-pound steel blade dropped from a crane. The guillotine made four cuts per plane, severing the wings and leaving the fuselage in three segments.

  The dissected bombers were left in place for three months after the cuts. The waiting period was not accidental. It gave Russian satellites time to photograph the wreckage and confirm that the aircraft had genuinely been destroyed, a tangible example of the verification principles built into the treaty's design.

  After the Soviet Union dissolved in 1991, the treaty's obligations cascaded across its successor states. Twelve republics inherited some form of nuclear-related obligation. Turkmenistan and Uzbekistan each eliminated one nuclear-related site and were released from ongoing inspections. Continuous inspections continued in Belarus, Kazakhstan, the Russian Federation, and Ukraine. Belarus, Kazakhstan, and Ukraine each committed to becoming non-nuclear-weapons states under the Nuclear Non-Proliferation Treaty of 1968, a commitment formalized through the 1992 Lisbon Protocol. All three eventually transferred or disposed of their inherited Soviet weapons, and the United States and Russia each reduced their delivery vehicles to the treaty ceiling of 1,600.

• 7. Expiration and What Followed

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  START I expired on the 5th of December 2009. A US State Department report released on the 28th of July 2010 concluded that Russia had not been in full compliance with the treaty at the time it expired, though the report did not identify the specific violations.

  Both sides had already been negotiating a replacement. A joint understanding signed by Barack Obama and Dmitry Medvedev in Moscow on the 6th of July 2009 set a target of reducing deployed warheads on each side to between 1,500 and 1,675, carried on 500 to 1,100 delivery systems. The successor treaty, known as New START, was signed in Prague on the 8th of April 2010. It entered into force on the 5th of February 2011 after ratification by the US Senate and Russia's Federal Assembly.

  New START imposed limits that were substantially lower than START I had required. It capped deployed nuclear warheads at 1,550, which was 74 percent fewer than the 6,000 allowed under the 1991 treaty and 30 percent fewer than the ceiling set by the 2002 Treaty of Moscow. Both sides were also limited to 800 total deployed and non-deployed launchers and heavy bombers. On the 21st of February 2023, Russia suspended its participation in New START, though it stated it would continue to observe the treaty's numerical limits. New START officially expired on the 5th of February 2026, leaving no successor treaty in place.