New START Expires: The 50-Year History of U.S.-Russia Arms Control Treaties

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For the first time since Richard Nixon met Leonid Brezhnev in Moscow, the United States and Russia have no active treaty framework limiting their nuclear arsenals. The treaty officially expired on February 5, 2026, ending a fifty-year run of agreements between the US and Soviet Union that survived the Cold War, the Soviet Union’s collapse, and every subsequent crisis short of this one.

What’s gone isn’t a treaty. It’s the system that let them check on each other—the inspections, the data exchanges, the satellite monitoring protocols. Without it, each nation can deploy thousands of additional warheads with minimal warning. The risk isn’t that either side wants a nuclear war. The risk is miscalculation in a future crisis when neither knows exactly what the other has deployed or where.

Understanding how we got here requires looking at the entire arc: from the freeze agreements in 1972 through the verification innovations of the 1980s, the post-Cold War reductions, and finally the slow-motion collapse that began when George W. Bush withdrew from the Anti-Ballistic Missile Treaty in 2002. Each new treaty learned from problems in the old one. Each also created problems that would cause future disagreements that would eventually destroy the system.

SALT I and Mutual Vulnerability (1972)

When Nixon and Brezhnev signed SALT I on May 26, 1972, they froze existing levels rather than negotiate equality. If either side wanted to add new submarine-launched missiles, they had to dismantle an equal number of older systems first. This wasn’t disarmament. It was an agreement not to make things worse.

The treaty rested on a concept of mutual vulnerability: both sides could retaliate if attacked first. If both could retaliate after absorbing an attack, neither would launch one. The companion Anti-Ballistic Missile Treaty addressed a different problem. If one nation developed an effective missile shield while the other didn’t, the balance would collapse. The ABM Treaty limited each side to two defensive sites—later reduced to one—ensuring neither could protect its territory from retaliation.

What made SALT I work was verification. The United States and Soviet Union agreed to use spy satellites without explicitly acknowledging they were monitoring each other’s territory. This careful wording let the Soviets avoid officially admitting American satellites violated their sovereignty. The treaty prohibited interfering with each other’s surveillance, establishing that spying on nuclear weapons was necessary, even if not openly acknowledged.

SALT II and the Counting Problem (1979)

SALT I was always meant to be temporary, a holding pattern while serious reduction talks happened. The challenge wasn’t agreeing on numbers. It was defining what to count.

Both sides had developed missiles carrying multiple separate warheads that could hit different targets. A submarine could carry sixteen missiles, each with eight warheads, putting 128 warheads on one vessel. Counting warheads required either physically inspecting every storage facility—politically impossible—or developing assumptions about how many warheads each missile type carried. SALT II used a system where they agreed to count each missile as carrying a certain number of warheads whether it did or not. This only worked if both sides told the truth.

The completed agreement, signed in Vienna on June 18, 1979, represented genuine progress on paper. In practice, SALT II became caught up in broader political conflicts. Both sides observed its terms for years anyway, indicating the restraint was valued despite the political breakdown.

Reagan and the INF Treaty (1987)

Ronald Reagan came to office believing the only language the Soviets understood was American strength. He continued observing SALT II limits even though the treaty was unratified, but Reagan pursued a massive military buildup designed to force Moscow to negotiate from weakness. By Reagan’s second term, the Soviet Union, weakened by the cost of military competition and economic problems, began seeking accommodation. When Mikhail Gorbachev came to power in 1985, things changed.

The result was the Intermediate-Range Nuclear Forces Treaty, signed December 8, 1987. For the first time, they didn’t just limit weapons. They destroyed an entire type of missile. The INF Treaty required destroying all ground-launched cruise missiles and intermediate-range ballistic missiles with ranges between 500 and 5,500 kilometers. Over 2,000 missiles were eventually destroyed.

More significant for verification, INF included on-site inspections on a scale never seen before. American and Soviet inspectors could visit each other’s facilities on short notice. The INF Treaty’s verification provisions established a template for subsequent agreements. Instead of relying solely on satellites and assumptions, the treaty created permanent inspection regimes. Inspectors could monitor production facilities, verify weapon elimination, and build confidence that compliance was genuine.

In 2019, the Trump administration withdrew. Russia denied the violation and reciprocally withdrew. Thirty-two years of continuous verification ended because one side convinced itself the other had cheated and that withdrawal served American interests better than continued verification.

START I and the Soviet Collapse (1991-2001)

The Soviet Union’s dissolution in 1991 created a negotiating environment never seen before. George H.W. Bush seized the opportunity to pursue the Strategic Arms Reduction Treaty Reagan had begun. START I represented genuine reduction, not a freeze.

Implementation revealed new verification challenges. When the Soviet Union dissolved, four newly independent states—Russia, Ukraine, Kazakhstan, and Belarus—possessed strategic nuclear weapons on their territories. These successor states had to be integrated into the treaty framework. The United States provided financial and technical assistance to help secure arsenals and eventually repatriate warheads to Russia for destruction.

START I’s verification provisions reflected INF lessons while adapting to vastly larger scale. Each side could conduct on-site inspections—both announced and short-notice—at a scale unimaginable during the Cold War. American inspectors visited Soviet missile production facilities, submarine bases, storage sites. Russian inspectors did the same in the United States.

START I entered into force in December 1994 and represented the high-water mark of mutual transparency. Both sides completed required reductions by December 5, 2001, and continued observing limits for an additional eight years. The treaty demonstrated that deep verification could work, that inspectors could distinguish compliance from deception, that adversaries could build sufficient confidence through transparency to maintain stable limits.

When the treaty approached its natural expiration in 2009, no successor was in place. The United States and Russia would eventually negotiate New START, but the failure to maintain continuity—the gap between START I’s expiration and New START’s entry into force in 2011—previewed the problem that would eventually destroy the system.

START II’s Failure (1993-2002)

START II was signed in January 1993 and represented ambitious reduction to 3,000-3,500 warheads per side with complete elimination of all land-based multiple-warhead ICBMs.

The U.S. Senate ratified START II on January 26, 1996. Russia’s Duma didn’t vote to approve until April 14, 2000—more than seven years later. Even then, Russian ratification came with conditions. The Duma’s resolution linked START II compliance to continued adherence to the 1972 Anti-Ballistic Missile Treaty, making explicit that further Russian reductions depended on American restraint in missile defense.

The delay reflected both political opposition from hardliners and broader concerns about American strategy. Critics in Moscow argued START II favored American submarines and bombers while restricting Russian land-based missiles that formed the backbone of Russian strategic forces. They feared that if Russia eliminated heavy ICBMs as START II required, it would be vulnerable to an American attack if the United States developed effective missile defenses.

In June 2002, the Bush administration withdrew from the Anti-Ballistic Missile Treaty, announcing it would develop a national missile defense system free from 1972 constraints. The administration argued missile defense was necessary to counter threats from “rogue states” like North Korea and Iran. American officials insisted defenses need not undermine Russian security because they would be limited in scope.

Russian officials rejected this reassurance. They understood missile defense technology could evolve, that 50 interceptors today could become 1,000 tomorrow, and that if the United States developed effective defense while Russia proceeded with START II reductions, Moscow would lose its second-strike capability. The ABM Treaty withdrawal effectively killed START II, even though the treaty technically remained unsigned by Russia.

The withdrawal revealed a tension in American strategy. American officials believed defensive systems enhanced security by making offensive weapons less valuable. Russian officials believed defenses destabilized the deterrent balance by creating the possibility of a disarming attack. The Bush decision signaled that the United States would prioritize unilateral military advantage over bilateral constraint when the two conflicted.

SORT: Minimal Arms Control (2002-2012)

START II’s failure left the United States and Russia in a peculiar position: both had publicly committed to major reductions, but no binding treaty enforced those commitments. The result was SORT—the Strategic Offensive Reductions Treaty, signed May 24, 2002.

SORT was arms control in its most minimal form. Rather than specifying how many warheads each side must deploy or how to verify compliance, SORT simply required each side to reduce deployed strategic warheads to between 1,700 and 2,200 by December 31, 2012. Each side could determine its own structure and composition. The treaty included no verification provisions specific to SORT, instead relying on mechanisms established under START I, even though the two treaties used different counting rules. SORT explicitly allowed either side to withdraw with three months’ notice if “extraordinary events” jeopardized its security.

SORT’s weakness reflected a significant shift in American strategic thinking. Rather than negotiate detailed deployment limits, the Bush administration preferred flexibility. It wanted to maintain the option to increase deployed warheads quickly if circumstances demanded, without being constrained by treaty prohibitions.

New START: Obama’s Reset (2010-2026)

Barack Obama came to office in 2009 committed to a “reset” of American-Russian relations and renewing the stalled arms control process. His secretary of state, Hillary Clinton, tasked Rose Gottemoeller, a veteran negotiator, with negotiating a new treaty in less than a year—a process that had taken nearly a decade for the original START. What emerged was New START, signed April 8, 2010, and entered into force February 5, 2011.

New START represented a middle path between SORT’s minimal constraints and START I’s verification depth. The treaty limited each side to 1,550 deployed strategic warheads on 700 deployed delivery systems, representing approximately 30 percent reduction from previous SORT limits. The treaty addressed the warhead counting problem by including direct limits on deployed warheads rather than relying solely on counting rules. To verify warheads, the treaty permitted surprise inspections where inspectors could pick any missile to check and count the warheads.

New START’s verification regime was more streamlined than START I’s—fewer inspections, less detailed data exchanges, simplified counting rules—but retained key elements of mutual verification. Each side could conduct 18 on-site inspections per year. It required biannual data exchanges on numbers and locations of deployed and non-deployed strategic delivery systems. It mandated notification procedures and required missiles be marked with unique identifiers to facilitate monitoring. The treaty required that missile test signals remain visible to spy satellites.

The Senate ratified New START on December 22, 2010, by a vote of 71-26. The partisan breakdown reflected declining consensus on arms control. START I had passed 93-6. Republican opposition wasn’t grounded in technical objections but rather in broader skepticism of arms control treaties generally and concerns about Russian intentions. Yet the treaty passed because enough Republicans—including senior defense officials who supported strategic stability—recognized that some constraint on Russian forces was better than none.

Verification in Practice (2011-2026)

From 2011 to 2020, both nations conducted hundreds of on-site inspections, verifying warhead numbers and confirming deployed forces remained within treaty limits. Inspectors visited ICBM fields in North Dakota, South Dakota, Montana, Wyoming. They traveled to submarine bases in Connecticut and Georgia. They inspected strategic bomber bases in Louisiana and Nebraska. Russian inspectors conducted equivalent visits to American facilities. American inspectors visited Russian missile production facilities, submarine bases in the Russian Far East, bomber bases near the Arctic Circle.

The verification regime worked. Both sides remained within numerical limits. When the Trump administration claimed in February 2023 that Russia had violated New START, the accusation wasn’t that Russian forces exceeded treaty limits, but that Russia said it would stop following the treaty’s rules in response to American military aid to Ukraine. Russia clarified it would continue observing numerical limits while refusing to permit inspections or exchange data.

Russia said it would keep the numbers down but wouldn’t let inspectors check. This revealed something about what compliance meant. Russia wasn’t violating the treaty by deploying more warheads than permitted. It was refusing the transparency mechanisms that gave each side confidence in mutual compliance.

The COVID-19 pandemic disrupted verification in 2020 when both sides suspended on-site inspections. The inspections never resumed even after pandemic restrictions eased. This seventeen-month hiatus in verification procedures—from March 2020 through the treaty’s expiration in February 2026—proved significant. Without face-to-face inspections, without data exchanges, without ability to visit facilities and confirm declared weapon systems existed and remained within limits, both sides operated under heightened uncertainty about compliance and intentions.

By the time New START approached its scheduled expiration, the inspection system that had kept both sides from building too many weapons had stopped working. The political relationship between the United States and Russia, already damaged by tensions over 2016 election interference, had completely shattered over the 2022 Russian invasion of Ukraine and subsequent American military assistance to Kyiv.

Global Consequences: The Non-Proliferation Treaty Unravels

The global system that discourages countries from building nuclear weapons depends on the idea that nuclear powers want to reduce their weapons. The 1968 Nuclear Non-Proliferation Treaty requires nuclear powers to “pursue negotiations in good faith” toward nuclear disarmament.

For decades, American and Soviet/Russian leaders could point to SALT agreements, START treaties, and New START as evidence of genuine effort to reduce arsenals. The treaties were real. The reductions were measurable. The verification was transparent.

New START’s expiration without replacement undermines this claim. Other nations observing the collapse face a straightforward conclusion: if the two largest nuclear powers won’t constrain themselves, why should emerging nuclear powers voluntarily limit their own weapons?

India and Pakistan are both building more weapons, competing with each other and China. Pakistan has developed new ballistic missiles with ranges exceeding 2,000 kilometers and continues producing fissile material for additional warheads. India has tested intercontinental ballistic missiles capable of striking all of China and has begun deploying missiles that could carry multiple warheads.

Iran, long suspected of pursuing nuclear weapons capability despite its commitments under the Non-Proliferation Treaty and the Joint Comprehensive Plan of Action nuclear deal, can point to the US and Russia stopping limiting weapons. North Korea, which conducted nuclear weapons tests and developed ballistic missiles despite international agreements and sanctions, has demonstrated that nuclear weapons provide security in ways diplomatic agreements don’t. China, which has long refused to participate in bilateral arms control agreements with the United States, watches the American-Russian breakdown and concludes its strategy of expanding its nuclear force without constraint is vindicated.

The 2026 Review Conference of the Nuclear Non-Proliferation Treaty, scheduled for April-May 2026, will occur in the shadow of New START’s expiration. Non-nuclear weapons states will demand that the five nuclear weapons states explain how they intend to fulfill their NPT obligations to pursue disarmament when the most significant bilateral disarmament agreement has collapsed.

The core deal of the NPT—that non-nuclear countries would give up weapons while nuclear states pursued disarmament—was always an unequal trade. The non-nuclear states’ patience was sustained by visible progress of arms control treaties that demonstrated movement toward disarmament. With that demonstration gone, the NPT’s credibility will erode further.

The Numbers: What’s Available to Deploy

Russia has about 5,459 warheads total, with approximately 1,718 currently deployed, and the rest stored or waiting to be destroyed. The United States possesses approximately 5,177 total nuclear warheads, of which roughly 1,770 are deployed.

The United States possesses the ability to activate and deploy an additional 480 nuclear weapons on its bomber forces within weeks and an additional 950 on its submarine fleet within six months. To accomplish full deployment, the U.S. would need to reopen the missile silos on each of its 14 Ohio-class ballistic missile submarines that were sealed to comply with New START, and would need to put nuclear weapons back on B-52 bombers that were changed to carry regular bombs. Russia could add 1,114 more warheads from its stockpile to its deployed force of 1,718, bringing total deployed warheads to 2,832.

With New START’s expiration, neither side is constrained from conducting these uploads. Without verification procedures to monitor the process, without data exchanges to confirm warhead deployments, without inspection rights to ensure conversion of delivery vehicles hasn’t occurred, each side faces what experts call a rapid buildup of weapons. If one side suddenly deploys more warheads, the other will feel it has to do the same. Within months, both nations could double their deployed warhead numbers, creating a nuclear force posture more reminiscent of Cold War levels than contemporary strategic thinking.

Three Possible Futures

As of early 2026, three things could happen next.

Could They Make a New Deal? The US and Russia would agree that without binding limits, the balance becomes less stable and both countries have to spend much more money in nuclear force modernization and maintenance. They would negotiate a new treaty that brings back numerical limits, restores verification procedures, and extends the treaty framework into the 2030s. Russia proposed both countries stick to the old limits without a formal treaty, in September 2025 when Putin suggested both nations voluntarily observe New START limits for one additional year. The Trump administration rejected this proposal, instead insisting any new agreement must include China.

History shows that when arms control agreements failed, new ones were negotiated later. When SALT II stalled, it took a new administration and a shift in political environment to negotiate START I. When the ABM Treaty expired, it took another change in administrations to pursue New START. A change in administration or a shift in strategic thinking could restore bilateral negotiation.

The obstacles are substantial. The Russian invasion of Ukraine has destroyed the diplomatic relationship in ways previous crises didn’t. Americans now see Russia as an aggressor, not just a rival. Russians see American weapons to Ukraine as the US fighting Russia indirectly. Neither side trusts the other’s motivations or intentions.

Could All Three Powers Agree? The Trump administration wants to include China in a new arms control agreement with the United States and Russia. If all three countries agreed to limit weapons at once, the global balance could be preserved. China has about 550 long-range missiles and has expressed no interest in joining trilateral negotiations when its arsenal is vastly smaller than those of the United States and Russia. Chinese officials have stated that as a threshold condition, the United States and Russia must reduce their forces to levels comparable to China’s, and only then could China participate in a limitation framework.

During Trump’s term in 2020, the administration proposed exactly this trilateral approach, and Chinese negotiators rejected it outright. There’s no indication Chinese thinking has shifted. China says that limiting weapons would weaken its defense at a time when it perceives rising threats from American military power in the Pacific. A trilateral agreement might eventually be negotiated, but the probability in the near term appears low.

Could They Make Separate Deals? Instead of one big agreement, the US, Russia, and other countries would make separate deals for different regions or types of weapons. The United States and Russia might agree to limits on intermediate-range missiles in Europe and Central Asia, even as they decline to constrain strategic forces. NATO might create a European system for nuclear weapons independent of Russian participation. The United States might negotiate bilateral limits with China on specific missile types while pursuing other agreements with Russia.

This would be a major change from the last fifty years of bilateral American-Russian strategic arms control. This would create separate regional agreements instead of one global treaty. Some regions might stay safer, but the arms race would continue.

The Challenge: Lost Expertise

Even if political will existed to resume bilateral arms control negotiations tomorrow, the effort would face a major challenge. The people who negotiated these treaties have mostly retired. The teams of negotiators who conducted SALT talks, START negotiations, and New START discussions have largely left. The knowledge about how to verify compliance and count weapons has been scattered. The State Department once had a large office dedicated to arms control but has cut its arms control staff compared to other priorities.

The US would need to hire and train new experts to negotiate a new agreement. New negotiators would need to understand how current weapons systems work—hypersonic missiles, underwater weapons, and new missile types that old treaties didn’t address. They would need to develop verification procedures for systems that operate differently than old monitoring methods. They would need to rebuild relationships with Russian negotiators and establish enough trust to share detailed information about nuclear weapons.

The technological landscape has shifted dramatically in the fifteen years since New START was negotiated. Both the United States and Russia have deployed hypersonic missile systems, advanced cruise missiles, and novel strategic systems that earlier arms control frameworks didn’t address. Russia’s underwater drone, which some call a “doomsday weapon” because it could destroy entire cities, operates so deep that inspectors can’t easily verify it. American Dark Eagle missiles can hit targets thousands of miles away with precision. These weapons are hard to monitor using old inspection methods. Negotiators would need to develop ways to count and monitor weapons with new capabilities and at speeds that exceed the monitoring capabilities that worked for traditional land-based and submarine missiles.

What’s at Stake

New START’s expiration ends fifty years of nuclear agreements. From SALT I in 1972 through New START in 2010, the US and the Soviet Union, and later Russia, agreed to limit their weapons. Despite its flaws, this stopped both sides from building as many weapons as they could. The framework survived wars, revolutions, leadership changes, and repeated crises that might easily have shattered it. Both sides knew that an unlimited arms race would cost more and be more dangerous than restrained competition under agreed rules.

The collapse didn’t happen because of one big failure or dramatic event. The Bush administration withdrew from the ABM Treaty and didn’t make a new one; different presidents pursued different arms control goals; administrations chose flexibility to change strategy instead of keeping agreements; the Senate voted against treaties for political reasons rather than because of security concerns; the US and Russia stopped trusting each other because of the Ukraine conflict; both countries stopped inspections during the pandemic and never restarted them; and the Trump administration insisted China join talks, but China refused.

Each decision seemed reasonable at the time. Together, they destroyed fifty years of agreements.

The UN Secretary General said New START’s expiration is a serious threat to world peace. For the first time since 1972, the US and Russia, which have 90% of the world’s nuclear weapons, have no treaty limiting how many they can deploy. Without inspections, information sharing, or trust, both countries can quickly deploy many more warheads. In a future crisis, both sides are much more likely to misunderstand each other and escalate.

After SALT II failed, it took ten years and the Soviet Union’s collapse before START I was negotiated. After the ABM Treaty ended, it took ten more years and a new president to negotiate New START. Once arms control breaks down, it takes years and significant political shifts to rebuild it.

In 2026, the world faces two problems: negotiating new treaties and rebuilding trust between the US and Russia—both sides recognizing they benefit from agreements, trusting that limits help both, and believing that inspections can verify compliance. Whether the US and Russia can trust each other again is the biggest question American leaders face as they deal with the collapse of fifty years of agreements.

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