For more than half a century, U.S.–Russian nuclear arms control has served as a central mechanism for managing strategic competition. Beginning with the 1972 Strategic Arms Limitation Talks (SALT I), successive agreements institutionalized transparency, predictability, and mutual restraint. New START, which entered into force in 2011, represents the culmination of this bilateral architecture. Its limits on deployed strategic warheads and delivery systems, combined with an intrusive verification regime, helped sustain stability even as geopolitical relations deteriorated.

However, Russia’s suspension of participation in 2023 and the treaty’s expiration in 2026 mark a significant turning point. The breakdown of the broader arms control framework—evident in the demise of the Anti-Ballistic Missile (ABM) Treaty in 2002, the Intermediate-Range Nuclear Forces (INF) Treaty in 2019, and the Open Skies Treaty in 2020—suggests a structural shift in the valuation of negotiated restraint. Assessing the prospects for post–New START arms control, it is important to consider these developments within both the historical context of bilateral relations and the shifting dynamics of current great power competition.

Academic debates on arms control offer a helpful context for understanding the current impasse. Traditional arms‑control theory, rooted in rationalist models, views treaty agreements as tools for reducing uncertainty, preventing arms races, and stabilizing deterrence. From this perspective, verification mechanisms and numerical limits mitigate the security dilemma by reducing incentives for worst‑case planning. While other scholars emphasize the role of domestic politics, bureaucratic interests, and leadership perceptions. Arms control agreements often reflect internal political coalitions, institutional preferences, and the ideological orientation of decision makers. The current U.S.-Russian environment, which is characterized by mutual suspicion and nationalist rhetoric complicates the formation of pro-arms control coalitions. Moreover, constructivist analyses highlight the normative dimension of arms control, arguing that treaties shape expectations, legitimize restraint, and embed cooperative practices. The erosion of these norms over the past decade has contributed to a broader delegitimization of negotiated limits.

These theoretical perspectives underscore that the challenges facing post–New START arms control are not merely technical but deeply embedded in political and normative contexts. The war in Ukraine has fundamentally reshaped U.S.-Russian relations. Moscow’s framing of the conflict as a confrontation with the West, combined with U.S. and allied NATO support for Ukraine, has created a political environment in which formal negotiations are viewed as strategically risky or politically unacceptable.

The U.S. seeks to address Russia’s large arsenal of non‑strategic nuclear weapons and its development of novel systems such as nuclear-powered cruise missiles and hypersonic glide vehicles. Russia, in turn, prioritizes constraints on U.S. missile defenses and long-range conventional strike capabilities. These asymmetries complicate the search for mutually acceptable trade-offs. Furthermore, verification has long been a cornerstone of bilateral arms control. Russia’s suspension of inspections and data exchanges under New START has undermined transparency and raised questions about the feasibility of future verification regimes. Designing agreements that satisfy both sides’ security concerns will be a central challenge.

The U.S. increasingly argues that future arms control must account for China’s expanding nuclear arsenal. Russia rejects trilateral frameworks, viewing them as attempts to dilute U.S.–Russian parity. Thus far, China shows little interest in formal arms control negotiations. This triangular dynamic introduces new complexities absent from earlier bilateral negotiations.

Despite the hostile political environment, arms control still matters. The strategic reasons for arms control include specific factors that deserve attention from states. Agreements reduce incentives for preemption and miscalculation, which can increase crisis stability. Data exchanges and inspections improve transparency by reducing uncertainty and reliance on worst-case assumptions. Arms races can impose significant economic burdens, even for the U.S.’ trillion-dollar defense budget and Russia’s constrained economy. Finally, U.S.–Russian cooperation reinforces the legitimacy of the global nonproliferation regime. These lasting incentives suggest that both states have structural reasons to pursue at least minimal engagement.

So, what are the pathways for Post–New START arms control? Political commitments to maintain New START limits, even without a formal treaty, could involve both sides making parallel political statements to uphold New START’s numerical limits. While these have no legal force, such commitments could help prevent rapid nuclear arsenal expansion and maintain stability and predictability.

Other paths could include more Issue‑Specific or Modular Agreements. Rather than pursuing a new comprehensive treaty, negotiators could focus on discrete issues, such as notifications of major strategic exercises, transparency measures for new strategic systems, and agreements to avoid dangerous military incidents. These modular arrangements could serve as building blocks for more ambitious frameworks. Next, revitalizing crisis‑management mechanisms by reestablishing military-to-military communication channels could reduce the risk of inadvertent escalation. Such mechanisms do not require treaty-level negotiations and can function even amid broader political tensions. Finally, promote multilateral and norm-building initiatives such as broader dialogues involving China, NATO allies, and other nuclear-armed states to help shape norms around transparency and risk reduction. Multilateral workshops, data exchange initiatives, or voluntary reporting mechanisms may be more practical than formal treaties.

The expiration of New START marks a critical turning point in the history of U.S.–Russian nuclear arms control. The structural, political, and technological challenges facing a successor agreement are formidable, and a new comprehensive treaty is unlikely in the near term. Yet the logic of arms control, rooted in the need to manage existential risks, remains important. Incremental, issue-specific, and politically binding measures offer a pragmatic path forward, preserving essential elements of strategic stability until conditions allow for more ambitious negotiations. The future of arms control will depend not only on geopolitical developments but also on policymakers’ ability to adapt traditional frameworks to a more complex, multipolar nuclear landscape. Without some form of negotiated restraint, the world risks entering an era of unconstrained nuclear competition for the first time in over half a century.

Stephen J. Cimbala is Distinguished Professor of Political Science at Penn State Brandywine and the author of numerous works on nuclear deterrence, arms control, and military strategy. He is a senior fellow at NIDS and a recent contributor to the Routledge Handbook of Soviet and Russian Military Studies edited by Dr. Alexander Hill (Routledge: 2025). The views of the author are his own.

Beyond New START: Prospects for U.S.–Russian Nuclear Arms Control was originally published on Global Security Review.

Hypersonic weapons, capable of exceeding Mach 5 with unpredictable flight paths, shatter the bedrock principles of conventional missile defense. Their ability to glide and maneuver within the atmosphere allows them to evade radar detection and interceptor systems, compressing warning times to mere minutes. This drastic reduction in reaction time amplifies the risk of miscalculations and accidental escalation, particularly in moments of crisis.

The global balance of power is being fundamentally altered, not merely adjusted, by the aggressive pursuit of maneuverable hypersonic weapon capabilities. China’s DF-17 hypersonic missile, coupled with its reported testing of a fractional orbital bombardment system (FOBS) with a hypersonic payload, demonstrates a clear intent to achieve global strike capabilities with minimal warning. Russia’s deployment of the Avangard HGV on its SS-19 intercontinental ballistic missiles and the operational status of the Zircon hypersonic anti-ship missile further highlight the growing proliferation of these advanced weapons. North Korea’s claim of successful hypersonic missile tests, while requiring verification, signal a potential integration of these weapons into its theater nuclear strategy, adding another layer of complexity to regional security.

The inherent capacity of maneuverable hypersonic weapons to render existing missile defense systems obsolete signifies not just a technological leap, but a deliberate dismantling of established strategic certainties. The unpredictability of their flight paths and the compression of warning times do not just complicate defense planning; they erode the very foundation of strategic stability, where deterrence relies on the certainty of retaliation. The potential for these weapons to carry both conventional and nuclear payloads does not just increase their versatility; it blurs the lines between conventional and nuclear conflict, creating a perilous ambiguity that heightens the risk of miscalculation.

The ability to strike targets with minimal warning does not just enhance offensive capabilities; it creates a coercive tool, enabling states to exert pressure and achieve strategic objectives without resorting to large-scale conventional warfare. The potential for hypersonic weapons to be deployed in a first-strike role does not just raise concerns about escalation; it fundamentally alters the calculus of deterrence, where the threat of retaliation may no longer be sufficient to prevent aggression.

To counter this burgeoning vulnerability, the United States must not merely react, but fundamentally redefine its strategic posture, acknowledging that piecemeal technological solutions are insufficient to address the profound shift hypersonic weapons impose on the security landscape. The rapid development of the glide phase interceptor (GPI) and space-based tracking systems is not just about enhancing missile defense; it is about restoring a sense of strategic stability, reassuring allies and deterring potential adversaries. The expansion of conventional hypersonic programs, such as the AGM-183 ARRW, conventional prompt strike, and the long-range hypersonic weapon, is not just about developing counterforce capabilities; it is about demonstrating a commitment to maintaining a credible deterrent, signaling to potential adversaries that aggression will be met with a swift and decisive response. The integration of hypersonic weapons into existing military doctrines does not just require tactical adjustments; it demands a fundamental reevaluation of strategic thinking, adapting to a new era of high-speed warfare.

The international community’s response to hypersonic weapons must not be limited to national defense initiatives; it must include a concerted effort to promote arms control and transparency. The absence of clear international norms and regulations regarding hypersonic weapons does not just create uncertainty; it fosters a climate of strategic competition, where states are incentivized to develop and deploy these weapons without restraint. The development of transparency and confidence-building measures is not just about reducing the risk of miscalculation; it is about building a foundation for strategic stability, where states can engage in dialogue and cooperation to mitigate the risks posed by these advanced weapons.

Hypersonic weapons represent a paradigm shift in military technology, fundamentally questioning if the world is entering a new era of vulnerability, undermining the foundations of traditional missile defense and reshaping the strategic landscape. Addressing this challenge requires a comprehensive approach that combines technological innovation, strategic adaptation, and international cooperation. Only through a concerted effort can the international community hope to mitigate the risks posed by hypersonic weapons and ensure a more stable and secure future.

Brandon Toliver, PhD, serves on the A4 staff of Headquarters Air Force. The views expressed are those of the author and do not reflect the official guidance or position of the United States government, the Department of Defense, the United States Air Force, or the United States Space Force.

Hypersonic Weapons: Are We Entering a New Era of Vulnerability? was originally published on Global Security Review.