I constrains present here a synthetic overview of the European security environment following the termination of all major missile arms-control agreements. This development represents a profound deterioration in the security architecture that had shaped strategic stability for decades. A significant portion of contemporary public anxiety and the heightened perception of war risk can be traced to this process.
Most importantly, the U.S.–Russia missile arms-control regime has effectively collapsed. First, the Anti-Ballistic Missile (ABM) Treaty ended, then the Intermediate-Range Nuclear Forces (INF) Treaty collapsed, followed by Russia’s suspension of its participation in New START, and finally, on February 5, 2026, New START expired without a successor agreement. Consequently, for the first time in more than fifty years, there is no legally binding treaty limiting the strategic nuclear arsenals of the United States and Russia.
1. Which treaties constrained missile systems?
ABM Treaty — Anti-Ballistic Missile Treaty (1972–2002)
The ABM Treaty restricted missile defense systems. Its strategic logic was paradoxical yet stabilizing: if neither side could effectively neutralize the opponent’s retaliatory capability, the incentive for a first strike would be reduced. In 2001, President George W. Bush announced the U.S. withdrawal, and the treaty formally ceased to apply in 2002. The principal rationale was the intention to develop defenses against so-called “rogue states,” particularly Iran and North Korea.
This did not constitute a formal treaty violation by the United States; rather, it was a lawful withdrawal under treaty provisions. Russia nevertheless argued that the expansion of U.S. missile defense capabilities undermined strategic equilibrium and subsequently used this argument to justify the development of new offensive systems.
INF Treaty — Intermediate-Range Nuclear Forces Treaty (1987–2019)
The INF Treaty prohibited land-based ballistic and cruise missiles with ranges between 500 and 5,500 kilometers, regardless of whether they carried nuclear or conventional warheads. It represented one of the most important security arrangements for Europe because it eliminated an entire class of weapons capable of rapidly striking European capitals.
As early as 2014, the United States officially concluded that Russia was violating the INF Treaty through the production and testing of a prohibited ground-launched cruise missile. The specific system later identified was the 9M729 missile, designated SSC-8 in NATO terminology. In December 2018, the United States characterized the violation as a “material breach” of the treaty. NATO unanimously supported the U.S. assessment.
In 2019, the United States suspended implementation of the treaty and formally withdrew. Russia denied any violations, but the treaty nonetheless ceased to exist.
New START — Strategic Delivery Systems and Warheads (2011–2026)
New START imposed limits on strategic delivery systems and warheads, specifically capping each side at 1,550 deployed strategic warheads and 700 deployed missiles and bombers. The treaty also established inspection procedures, data exchanges, and verification mechanisms.
Beginning in 2022, Russia obstructed inspection activities, and in 2023 President Putin announced a “suspension” of Russia’s participation in the treaty. The United States considered this legally invalid and a violation of treaty obligations. Although the agreement formally remained in force until February 5, 2026, it expired on that date without a replacement framework.
2. What evidence exists regarding Russian treaty violations?
The strongest and best-documented case concerns the INF Treaty and the 9M729 / SSC-8 missile system.
Evidence 1: Testing patterns designed to circumvent the literal provisions of INF
According to U.S. assessments, Russia tested the same missile in two configurations: initially from a fixed launcher at ranges exceeding 500 kilometers, and subsequently from a mobile ground launcher at ranges below 500 kilometers. Each test, considered separately, could be presented as technically compliant; taken together, however, they demonstrated the capability of a mobile ground-launched cruise missile operating within the range prohibited by INF.
This interpretation was presented, among others, by then-U.S. Director of National Intelligence Daniel Coats.
This constitutes the central evidentiary argument: the issue was not simply the missile designation itself, but rather the combination of a range exceeding 500 kilometers and a mobile ground-based launch platform.
Evidence 2: Production and deployment beyond experimental testing
The United States and NATO asserted that Russia not only tested but also developed and deployed the 9M729 system. NATO officially stated that all Allied governments agreed that the SSC-8/9M729 system violated INF and represented a significant threat to Euro-Atlantic security.
This distinction is important because INF prohibited not only operational use but also possession, production, and testing of such systems and their launch platforms.
Evidence 3: Estimated operational range of the 9M729
The Missile Threat Project at CSIS estimated the range of the 9M729 / SSC-8 at approximately 2,500 kilometers, placing it well within the prohibited INF range of 500–5,500 kilometers.
If this assessment is accurate, the system was not a borderline case but rather a textbook example of an intermediate-range missile prohibited under INF.
Evidence 4: Russia’s public presentation of the 9M729 failed to convince NATO
In January 2019, Russia publicly displayed the 9M729 system and argued that its range did not exceed treaty limitations. NATO and the United States considered the presentation inadequate; according to U.S. intelligence assessments, the displayed equipment and technical diagrams did not correspond to the system previously observed and assessed as the operational 9M729 configuration.
In other words, Russia denied the allegations but did not permit a level of verification capable of conclusively resolving the dispute.
Evidence 5: Subsequent operational use against Ukraine
Following the collapse of INF, additional technical indicators emerged. Reuters reported in 2025–2026 that Ukraine and independent experts identified Russian use of 9M729 missiles against Ukrainian targets, with one missile reportedly traveling more than 1,200 kilometers.
This does not constitute evidence from the period during which INF remained in force, but it does support the assessment that the system possessed precisely the capabilities that had been central to the original dispute.
3. Did Russia also violate New START?
Two issues should be distinguished.
First, the United States concluded that Russia violated New START verification obligations by refusing on-site inspections and by failing to convene or resume the work of the Bilateral Consultative Commission. This significantly impaired U.S. capacity to assess Russian compliance.
Second, for a prolonged period, publicly available U.S. assessments did not conclusively state that Russia had substantially exceeded the treaty’s central numerical limits on warheads and delivery systems. The principal concern was that Russia dismantled the transparency framework: inspections, data exchanges, and notification mechanisms.
By 2024, the United States stated that it could no longer certify full Russian compliance, and analyses suggested that Russia may have approached or temporarily exceeded treaty limits by small margins. However, this did not constitute a case as clear-cut as the 9M729 issue under INF.
4. Was Russia solely responsible for the erosion of the arms-control system?
No. The picture is more complex.
The United States legally withdrew from the ABM Treaty in 2002, a decision Russia viewed as a major challenge to strategic stability. The United States also withdrew from INF in 2019, although this followed years of allegations against Russia and NATO support for those allegations.
Russia, for its part, was assessed by the United States and NATO as violating INF, suspended implementation of New START, withdrew from the CFE Treaty in 2023, and had previously reduced its participation in broader European arms-control arrangements. Russia often claims that the MK-41 launchers used in Aegis Ashore could technically launch Tomahawk missiles, but NATO maintains that the installations in Poland and Romania are configured as defensive systems equipped with SM-3 interceptors. This dispute was one of the Russian propaganda arguments after the collapse of the INF Treaty.
For a long time, NATO in Europe had a gap in the 500–2,500 km range category for ground-launched strike missiles. This gap was supposed to begin being filled by U.S. Typhon / Tomahawk / SM-6 / Dark Eagle systems in Germany from 2026 onward, but according to reports from May 2026, the future of that deployment has become politically uncertain.
In summary, the United States also made decisions that weakened the treaty architecture, particularly concerning ABM. However, the most concrete and extensively documented case of a missile-related treaty violation concerns Russia’s 9M729 system under INF.
5. Strategic implications
Following the expiration of New START in February 2026, no comprehensive legally binding framework remains to constrain the strategic nuclear forces of the United States and Russia. In addition, the collapse of INF permits both sides to develop land-based intermediate-range missile systems.
For Europe, this implies the return of strategic conditions reminiscent of the 1980s: reduced warning times, elevated risks of miscalculation, and the potential deployment of missile systems capable of striking targets throughout the European continent.
From the perspective of strategic studies and security scholarship, many researchers regard transparency mechanisms, verification procedures, and legally binding constraints not merely as technical instruments but as fundamental stabilizing elements within the broader architecture of international security. Their erosion increases uncertainty, weakens predictability, and may heighten the probability of unintended escalation.
