Treaties in Limbo: What New START Reveals About Suspension and Compliance Under Treaty Law

Arms control treaties reveal a structural tension within international treaty law. Although such agreements rely on substantive limits on nuclear forces, their effectiveness depends equally on verification and compliance mechanisms that promote clarity and trust among treaty parties.[i] When functioning properly, these mechanisms allow states to assess compliance and reduce the risk of miscalculation, arms racing, or premature escalation.[ii] Russia’s 2023 unilateral suspension of its participation in the New START Treaty, while the treaty remained formally in force, is a prime example of how prolonged nonperformance can undermine this framework.[iii] While international law provides detailed rules governing breaches, suspensions, and withdrawals, it offers little direct guidance for treaties that remain formally in force while core obligations are unilaterally suspended in practice for extended periods.[iv]

The Vienna Convention on the Law of Treaties (“VCLT”) sets out the rules for the formation, interpretation, and termination of treaties. Under the Convention, parties may withdraw pursuant to treaty terms or mutual consent, and material breaches may justify suspension or termination in limited circumstances.[v] The International Law Commission’s commentary treats suspension as an exceptional and temporary measure intended to preserve the treaty relationship while encouraging a return to performance.[vi] The VCLT itself, however, does not specify the permissible duration or scope of suspension, nor does it lay out legal consequences that follow when a unilateral suspension effectively disables a treaty’s core operational mechanisms.[vii]

This omission matters most in the context of arms control. Nuclear weapons treaties regulate systems with uniquely catastrophic potential, and therefore they rely heavily on detailed verification measures such as on-site inspections, data exchanges, and notification requirements.[viii] These provisions are not merely procedural but central to treaty operation, as they allow each side to see what the other is doing and to assess compliance with a high degree of confidence.[ix] When those verification activities stop, even temporarily, the treaty loses much of its practical purpose and force.

The New START Treaty was a bilateral agreement between the United States and Russia that limited strategic nuclear forces and put in place detailed verification mechanisms, including on-site inspections and data exchanges. [x] Although the treaty formally remained in force until its expiration on February 6, 2026, its practical operation sharply diminished after Russia announced in 2023 that it would suspend participation in key implementation measures.[xi] In particular, Russia stopped allowing on-site inspections, paused the data exchanges and notifications required under the treaty’s verification regime, and declined to convene meetings of the Bilateral Consultative Commission.[xii] It justified these steps by pointing to broader security concerns and U.S. policy choices outside the treaty itself.[xiii] The result was a treaty that technically continued to exist but no longer functioned as designed. The VCLT says little about how long such a suspension may last, whether it can extend to obligations central to a treaty’s functioning, or whether it may be justified by political disputes outside the treaty itself.[xiv]

During this period, both parties continued to recognize New START’s numerical limits on nuclear weapons, yet the absence of inspections and routine data sharing made compliance increasingly difficult to verify.[xv] Russia’s suspension of inspections and treaty-required notifications significantly reduced the information available to monitor compliance.[xvi] The resulting lack of transparency was compounded by U.S. countermeasures that limited inspection-related cooperation.[xvii] As the verification system broke down, uncertainty grew, and each side was forced to rely more on assumptions rather than shared, verifiable information when gauging strategic risk.

 The New START experience illustrates a significant gap in treaty law. While the agreement remained officially in force, Russia’s suspension lasted for years and affected obligations central to the treaty’s operation, effectively hollowing it out without triggering withdrawal or termination.[xviii] This mismatch between the VCLT’s narrow conception of suspension and how modern arms control treaties operate in practice shows that international law offers no clear way to address long-term nonperformance that falls short of a formal exit.

Filling this gap does not require rewriting the law of treaties. It does, however, require closer attention to how suspension actually works in practice. Clearer rules on how long suspension can last, more precise limits on which obligations can be paused, and measures to keep at least basic verification and information sharing in place during disputes could help prevent future arms control agreements from drifting into prolonged legal limbo. Without these safeguards, treaties risk remaining formally intact while failing to carry out the stabilizing role that international law and the world expect of them. 

Caroline Zisette is a staff member of Fordham International Law Journal Volume XLIX.

[i] See Xiaodon Liang, The New START at a Glance, Arms Control Ass’n (Dec. 2024), https://www.armscontrol.org/factsheets/newstart (outlining New START’s reliance on numerical limits combined with inspections, data exchanges, and notifications to promote transparency and confidence).

[ii] See Anya L. Fink, U.S.-Russian Nuclear Arms Control: Overview and Potential Considerations for Congress, Cong. Rsch. Serv. IF12964 (Feb. 6, 2026), https://www.congress.gov/crs-product/IF12964.

[iii] See Xiaodon Liang & Daryl G. Kimball, New START on the Brink, Arms Control Ass’n (Jan.-Feb. 2026) https://www.armscontrol.org/act/2026-01/arms-control-today/new-start-brink.

[iv] See Vienna Convention on the Law of Treaties, May 23, 1969, 1155 U.N.T.S. 331, arts 54, 57, 60; Int’l Law Comm’n, Draft Articles on the Law of Treaties with Commentaries, 1966 Y.B. Int’l L. Comm’n, vol. II, at 251–53.

[v] See Vienna Convention on the Law of Treaties, supra note iv, arts. 54, 57, 60.

[vi] See Int’l Law Comm’n, supra note iv, at 251–53 (explaining the conditions under which suspension may be applied and the ILC’s view that it is intended to preserve the treaty while encouraging resumption of duties). 

[vii] See Vienna Convention on the Law of Treaties, supra note iv, arts. 57, 60; Int’l Law Comm’n, supra note iv, at 251–55.

[viii] See Liang, supra note i.

[ix] See Fink, supra note ii.

[x] See Liang & Kimball, supra note iii.

[xi] See Shannon Bugos, Russia Suspends New START, Arms Control Ass’n, (Mar. 2023) https://www.armscontrol.org/act/2023-03/news/russia-suspends-new-start.

[xii] See Id.

[xiii] See Id.

[xiv] See Vienna Convention on the Law of Treaties arts. 57, 60, supra note iv; Int’l Law Comm’n, supra note iv, at 251–55.

[xv] See Id.

[xvi] See Bureau of Arms Control and Nonproliferation, U.S. Countermeasures in Response to Russia’s Violations of the New START Treaty, U.S. Dep’t of State (June 1, 2023), https://www.state.gov/u-s-countermeasures-in-response-to-russias-violations-of-the-new-start-treaty#:~:text=INSPECTION%20ACTIVITIES%3A%20The%20United%20States,and%20by%20revoking%20the%20standing (describing U.S. reciprocal countermeasures restricting inspection-related cooperation).

[xvii] See Id.; See also Liang & Kimball, supra note iii. 

[xviii] See Bugos, supra note xi; Vienna Convention on the Law of Treaties arts. 57, 60, supra note iv; Int’l Law Comm’n, supra note iv, at 251–55.

This is a student blog post and in no way represents the views of the Fordham International Law Journal.