New START (New Strategic Arms Reduction Treaty)

New START (New Strategic Arms Reduction Treaty) is a bilateral arms control agreement between United States and Russian Federation that regulates the numerical limitation of strategic offensive weapons, their verification and transparency mechanisms, and mutual information exchange. The full name of the treaty is "Treaty on Measures for the Further Reduction and Limitation of Strategic Offensive Arms", and it is the last binding U.S.–Russian agreement signed in the post–Cold War era aimed at reducing nuclear weapons.

The New START Treaty was signed in Prague on 8 April 2010 and entered into force on 5 February 2011. It entered into force after approval by the United States Senate and the legislative body of the Russian Federation. The initial term of validity was set at 10 years, and the treaty text provided for a one-time extension of up to five years by mutual agreement. Accordingly, the treaty was extended for five years in February 2021 and remains in force until 5 February 2026.

The primary objective of the treaty is to establish numerical limits on deployed strategic nuclear warheads and the systems carrying them, enhance predictability regarding the strategic nuclear forces of both parties, and build mutual confidence through a verification regime. In this context, New START introduced a comprehensive framework covering not only the number of nuclear warheads but also intercontinental ballistic missiles, submarine-launched ballistic missiles, and nuclear-capable heavy bombers that carry these warheads.

The New START Treaty filled the legal vacuum created after the expiration of the 1991 START I Treaty and replaced the 2002 Strategic Offensive Reductions Treaty (SORT). In this sense, the treaty represents the continuation of a half-century-long bilateral nuclear arms control process between the United States and the Russian Federation. Throughout the treaty’s duration, both parties retained the freedom to determine the structure of their strategic forces within the established limits.

New START is not merely a text imposing numerical limits; it is a legal framework incorporating a comprehensive verification and transparency regime. The treaty includes provisions for on-site inspections, regular data exchanges, notification obligations, and the use of national technical means of verification. Through these mechanisms, both parties have consistently obtained reliable and verifiable information on the status of each other’s strategic nuclear forces.

The treaty ceased to be in force on 5 February 2026 upon expiration of its legal term.

Historical Background of the Treaty

The New START Treaty is the final chapter in the bilateral arms control process between the United States and the Russian Federation, which began during the Cold War and aimed at limiting nuclear weapons. The foundation of this process was the mutual capacity of both countries to destroy each other with strategic nuclear weapons, creating unpredictable risks. From the 1960s onward, the parties sought stability not through complete nuclear disarmament but through numerical limits and verification mechanisms.

The first comprehensive step was the interim agreement signed as a result of the 1972 Strategic Arms Limitation Talks (SALT I). SALT I limited the number of intercontinental ballistic missile (ICBM) and submarine-launched ballistic missile (SLBM) launchers but did not impose a direct numerical limit on warhead counts. This allowed for the deployment of multiple warheads per missile and failed to curb the growth of nuclear destructive capacity.

SALT II, signed in 1979, never entered into force. Following this period, negotiations for more comprehensive and binding arrangements accelerated. The 1991 START I Treaty was the first to establish comprehensive and verifiable limits on strategic nuclear warheads, launchers, and bombers. START I remained in force until 2009.

After the expiration of START I, the parties reached agreement on the 1993 START II Treaty, but it too never entered into force. START II aimed to eliminate heavy ICBMs equipped with multiple independently targetable reentry vehicles (MIRVs), but it was never implemented due to political and security considerations. The Russian Federation formally withdrew from START II after the United States withdrew from the 1972 Anti-Ballistic Missile (ABM) Treaty in 2002.

The Strategic Offensive Reductions Treaty (SORT), in force from 2002 to 2011, required both parties to reduce their deployed strategic warheads but offered a limited framework in terms of verification and monitoring mechanisms. SORT largely relied on the verification infrastructure of START I and did not establish its own comprehensive verification regime.

During this period, the expiration of the INF Treaty in 2019 and the earlier termination of the ABM Treaty led to a progressive decline in binding arms control agreements between the United States and Russia. As a result, the New START Treaty became, as of 2011, the only remaining major bilateral strategic nuclear arms control agreement between the two countries.

Legal and Structural Framework of the Treaty

The treaty consists of three main levels. The first level is the main treaty text, which defines the fundamental rights and obligations of the parties. This text includes general principles and core articles on the limitation of strategic offensive weapons, along with a preamble. The second level is the Protocol, attached to the main text, which details implementation provisions such as definitions, verification procedures, inspection rules, and notification mechanisms. The third level comprises the Technical Annexes appended to the Protocol, which provide detailed regulations on technical matters such as inspection procedures and data formats.

The initial term of validity of the New START Treaty was set at ten years. According to the treaty text, the parties may extend the treaty by up to five years, once only, by mutual agreement. In accordance with this provision, the United States and the Russian Federation agreed in February 2021 to extend the treaty until 5 February 2026. The extension took effect under the mechanism provided in the treaty without requiring a new ratification process.

The treaty also includes a withdrawal clause. Under this provision, either party may withdraw if it determines that extraordinary events related to its supreme national interests have jeopardized the treaty. The withdrawing party is required to provide advance notice to the other party.

The New START Treaty does not directly prohibit or limit missile defense systems or conventional long-range strike capabilities. However, the treaty’s preamble acknowledges the interrelationship between strategic offensive weapons and strategic defensive weapons. Nevertheless, the treaty’s provisions apply exclusively to the limitation of strategic offensive weapons.

The New START Treaty is implemented through the Bilateral Consultative Commission (BCC), a consultative mechanism designed to interpret, implement, and resolve technical issues related to the treaty. The BCC is expected to meet regularly and serve as a direct communication channel between the parties.

Numerical Limits and Core Obligations

The New START Treaty established quantitative and binding upper limits on the strategic offensive weapons of both parties. The limits set by the treaty cover not only the total number of nuclear warheads but also the systems and launch infrastructure carrying them. These limits became binding seven years after the treaty entered into force, that is, on 5 February 2018.

Under the treaty, each party is limited to a maximum of 1,550 deployed strategic nuclear warheads. This cap includes warheads on deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and nuclear-capable heavy bombers. According to the treaty, each deployed heavy bomber is counted as one warhead, regardless of its actual carrying capacity.

New START also established separate and clear limits for strategic delivery systems. The total number of deployed ICBMs, deployed SLBMs, and nuclear-capable heavy bombers is limited to a maximum of 700. This limit applies to systems actively deployed for strategic nuclear missions.

The treaty also defines a broader upper limit. The combined total of deployed and non-deployed launchers and bombers is capped at 800. This category includes ICBM silos, mobile launchers, submarine launch tubes, and nuclear-capable heavy bombers. Systems used for training, testing, or maintenance are also counted as non-deployed elements under this limit.

New START does not impose a direct numerical limit on non-deployed nuclear warheads. Similarly, non-deployed missiles are not numerically limited, but they must be stored in designated facilities, labeled, and included in the notification system. This arrangement is designed as a transparency mechanism to prevent the covert rapid deployment of non-deployed systems.

Counting Rules and Definitions

To ensure the enforceability of its numerical limits, the New START Treaty established detailed and binding counting rules and a comprehensive definition system. The treaty clearly specifies under what conditions weapons and systems are classified as “deployed” or “non-deployed.”

In the treaty, the term “deployed” is defined differently depending on the type of weapon system. For ICBMs and SLBMs, a system is considered deployed if it is installed on an active launcher. Strategic bombers are considered deployed if they are assigned to nuclear missions. Conversely, missiles not mounted on launchers and systems not in operational service are classified as “non-deployed”.

The treaty also clearly defines the concept of a warhead. For deployed ICBMs and SLBMs, the number of warheads is calculated based on the actual number of re-entry vehicles mounted. This approach, unlike some earlier treaties, relies on actual warhead counts rather than hypothetical estimates.

A special counting rule was adopted for heavy bombers. Each nuclear-capable heavy bomber is counted as one warhead, regardless of its actual nuclear payload capacity. This approach aims to simplify verification processes and enhance verifiability.

New START makes a clear distinction between delivery systems and launchers. ICBM silos, mobile land-based launchers, and submarine launch tubes are defined as launchers under the treaty. Strategic bombers are counted separately as both delivery systems and launchers within the counting regime.

Verification and Transparency Mechanisms

Under the treaty, each party is entitled to conduct up to 18 on-site inspections per year. Inspections are divided into two categories. Type One inspections are conducted at facilities housing both deployed and non-deployed strategic systems. These inspections aim to verify the number of warheads on deployed missiles, confirm the number of non-deployed launchers, and ensure compliance with treaty provisions. Type Two inspections focus exclusively on facilities housing non-deployed systems and are primarily concerned with verifying conversion, dismantlement, and maintenance activities.

The New START Treaty requires regular data exchanges and notification obligations. The parties share detailed information on the number, type, location, and status of their strategic offensive weapons. These data exchanges are carried out through periodic comprehensive notifications as well as a continuous notification system. Under this system, the parties are obligated to notify each other of developments such as the deployment, relocation, conversion, or dismantlement of missiles.

Implementation Process (2011–2020)

Following its entry into force on 5 February 2011, the New START Treaty entered a period of implementation during which the verification, notification, and inspection mechanisms were gradually activated. The treaty granted the parties a seven-year transition period to bring their strategic nuclear forces into compliance with the established numerical limits. During this period, the United States and the Russian Federation adjusted their strategic nuclear force structures to meet the treaty’s upper limits.

During this period, on-site inspections were regularly conducted. Both parties continued mutual inspection activities within the annual inspection quotas established by the treaty.

As required by the treaty, both the United States and the Russian Federation had to meet the established numerical limits by 5 February 2018. On that date, both parties officially confirmed that they had complied with the treaty’s upper limits.

2021 Extension Decision

As the initial term of the New START Treaty was set to expire on 5 February 2021, the parties evaluated the extension provision in the treaty text. In February 2021, the United States and the Russian Federation agreed to extend the New START Treaty until 5 February 2026.

It was specified that the extension would cover a single additional five-year period and that the treaty could not be extended a second time. Following the extension decision, the parties indicated that they could pursue negotiations on a replacement arrangement or new arms control framework during the extended validity period of New START.

Suspension of Implementation and Tensions (2022–2023)

The implementation of the New START Treaty was interrupted as of 2022. During this period, on-site inspections and meetings of the Bilateral Consultative Commission (BCC) were effectively suspended. The parties attributed the initial interruption to travel and health restrictions imposed due to the COVID-19 pandemic. Inspection activities were suspended in March 2020 and were never resumed.

In the second half of 2022, the United States initiated efforts to restore the verification mechanisms under the treaty. Washington called for the mutual resumption of inspections and BCC meetings. However, these efforts were reportedly rejected by the Russian Federation.

In February 2023, Russian President Vladimir Putin publicly announced that Russia was suspending implementation of the New START Treaty. He cited the United States’ support for Ukraine and the stance of Western countries toward Russia as justifications. The suspension decision did not constitute a legal withdrawal from the treaty.

Despite the suspension, the Russian Federation stated that it would continue to comply with the treaty’s central numerical limits. However, Russia halted participation in on-site inspections, data exchanges, and BCC meetings as stipulated by the treaty.

The United States characterized Russia’s stance as “irresponsible and unlawful”. The U.S. Department of State stated that, due to Russia’s refusal to permit inspections and its suspension of data sharing, Russia’s compliance with the treaty could no longer be verified since 2022. In response, the United States limited its own data sharing and denied Russia access to conduct inspections on U.S. facilities.

As a result, the New START Treaty, while legally still in force, was effectively implemented only in a limited manner during 2022–2023.

Termination of the Treaty (5 February 2026)

The New START Treaty officially expired on 5 February 2026 upon the conclusion of its extended term.

At the time of the treaty’s expiration, United Nations Secretary-General António Guterres, in an official statement issued from New York, described the end of New START as a critical turning point for international peace and security. He stated that for the first time in over half a century, there is no legally binding agreement limiting the strategic nuclear arsenals of the United States and the Russian Federation. The Secretary-General emphasized that decades of nuclear arms control agreements, from the Cold War-era Strategic Arms Limitation Talks to New START, had played a vital role in preventing catastrophe and reducing global nuclear stockpiles.

In his assessment, Guterres stated that “During and after the Cold War, nuclear arms control between these governments helped prevent disasters” and stressed that these frameworks had provided stability and “prevented catastrophic miscalculations”.

The Secretary-General also warned that the collapse of this limitation system coincides with a period of rising geopolitical tensions and the highest level of nuclear weapons use risk in decades.

Guterres noted that this turning point also presents an opportunity to redesign an arms control regime suited to the changing security environment. He welcomed statements by the presidents of both the United States and the Russian Federation acknowledging the destabilizing effects of a new nuclear arms race.

In his statement, Guterres said, “The world now awaits the Russian Federation and the United States to turn their words into action”, and called on both parties to “without delay” return to the negotiating table to agree on a successor framework that reestablishes verifiable limits, reduces risks, and strengthens global security.

Kremlin Spokesperson Dmitry Peskov, in a statement on 3 February, said, “In just a few days, the world will likely become more dangerous. For the first time, the two countries with the largest nuclear arsenals, the United States and Russia, will have no agreement limiting these arsenals.”

In his statement on 5 February, Peskov emphasized that New START is no longer in force, saying, “We view this negatively and express our regret. Our efforts to extend the limits by one year were met with no response.”

Regarding the steps his country will take following the treaty’s expiration, Peskov added, “Russia continues to adopt a responsible and cautious approach regarding the strategic stability of nuclear weapons and, as always, will prioritize its national interests.”

The Russian Ministry of Foreign Affairs stated that Russia’s attempt to extend New START was not reciprocated by the United States, adding, “We proceed from the fact that the parties are no longer bound by any obligations under the treaty and are free to choose their next steps.” The statement also indicated that Russia is prepared to take decisive military-technical measures to counter any potential threats to its national security.