Russian President Vladimir Putin announced Russia’s suspension of the New START Treaty on February 21. New START is the last remaining nuclear arms control agreement between Russia and the United States. The treaty limits the size of both arsenals to 1,550 nuclear warheads deployed on 700 strategic delivery systems—a combination of intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles, and long-range bombers. It also provides a verification procedure that allows officials from each country to inspect nuclear sites in the other.

While Russia has not officially withdrawn from the treaty, its suspension likely foreshadows the treaty’s demise. Future expansion of Russia’s nuclear arsenal is possible. However, the immediate concern is a resumption of nuclear testing. Russian president Vladimir Putin mentioned the possibility of testing in his announcement, directing Rosatom—Russia’s state-run nuclear energy company—to begin preparations for testing.

This testing will have two goals. First, Russia will use nuclear tests as a tool of coercive diplomacy. Tests will be timed to coincide with events of political or military importance. These tests could occur ahead of new offensives in Ukraine or an expansion of Russian attacks on civilian infrastructure. Beyond Ukraine, nuclear testing could precede efforts to destabilize other Russian neighbors, such as the potential plot to overthrow the Moldovan government.

These nuclear tests would serve as signals that Russia is willing to use its arsenal in the event of U.S. or NATO operations against Russia. In the case of Russian military operations—whether the current operation in Ukraine or future operations elsewhere—these tests could be part of a Russian strategy to prevent the escalation of a local conflict to a regional conflict. This escalation management is a central feature of Russian military doctrine. Experts have claimed that nuclear weapons are important tools for escalation management, although there is debate about how these weapons may be used or not used.

Russia already engages in nuclear signaling for these purposes. Putin and other Russian leaders have used nuclear threats repeatedly during and before the war in Ukraine. Nuclear-capable hypersonic weapons were deployed to Kaliningrad and Syria—where they would be within range of NATO capitals in Western Europe and the Mediterranean—in the weeks preceding the invasion. Nuclear testing would add another means for coercive nuclear signaling.

This strategy would not be uniquely Russian. North Korea also pairs nuclear testing with political objectives. North Korean tests often coincide with joint U.S.-South Korean military drills, the inauguration of new U.S. or South Korean presidents, or important events in U.S. relations with South Korea, Japan, or China.

The second goal of renewed nuclear testing is to improve Russia’s nuclear arsenal. Russia is currently engaged in a major nuclear modernization program. This modernization impacts all three legs of Russia’s nuclear triad and includes both upgrades to existing capabilities—such as developing the Sarmat ICBM or the Borei-A SSBN—and novel systems such as the Avangard hypersonic glide vehicle.

Both Russia and the United States have developed new warheads and delivery systems without detonating a nuclear weapon over the past few decades. Computer modeling has allowed both countries to design and evaluate new weapons. American nuclear maintenance and modernization through the Department of Energy’s Stockpile Stewardship Program have been a success. Officials expect to rely on Stockpile Stewardship rather than test detonations for the foreseeable future.

Russia’s military maintenance and modernization programs have not been as reliable as their American counterparts. Russia has experienced repeated military failures in Ukraine, despite a comprehensive and costly conventional modernization program following another shockingly poor performance during the 2008 Russo-Georgian War. Reports of corruption and ineptitude in Russia’s defense industry and military have surfaced, alleging that much of Russia’s investment in conventional modernization went into the pockets of various elites instead of into new and better equipment.

The failure of Russia’s conventional modernization has led to speculation about the state of Russia’s nuclear arsenal. The corruption and ineptitude of Russia’s defense industrial and military leadership may degrade the reliability of Russian weapons. Testing may allow Russian leaders to confirm the capabilities of new systems better than computer modeling, assuaging fears of an unreliable nuclear deterrent. Testing also shows adversaries that these weapons will work, improving the deterrent abilities of Russia’s nuclear arsenal.

If testing is to occur, it will most likely happen at Novaya Zemlya. The Arctic archipelago is heavily militarized and was one of the Soviet Union’s main nuclear testing sites. Tsar Bomba, the largest nuclear device designed and detonated, was tested there.

Russia has increased the development of military infrastructure and capabilities in its far north, including Novaya Zemlya, over the past several years. The region is perceived as critical to Russian security, and the resumption of nuclear testing would increase its strategic value to Moscow. This could lead to further militarization of the Russian Arctic. 

Increasing Arctic militarization would have significant strategic consequences for other Arctic powers, all of whom are current or aspiring NATO members. Russia has expanded its claims to the Arctic seafloor over the past few years, bringing its territorial claims into greater contact with those of Canada and Norway. Russia and Norway are also engaged in tense relations along their land and maritime Arctic borders. These disputes have become increasingly militarized. Increasing Russian military assets in the Arctic would exacerbate these disputes and increase the insecurity of other Arctic states, including the United States. 

While I would argue the impending death of New START is likely, it is not guaranteed. The United States should attempt to revive Russian participation in the deal. But it is unlikely that efforts will be successful, especially without concessions that are unacceptable to the United States and its allies.

Given the likely failure of diplomatic overtures to Moscow, the United States and NATO must be ready to deal with the resumption of Russian nuclear testing. American nuclear testing is probably not necessary. However, improving defenses in the Arctic—a region the United States has deprioritized—is. In addition to developing its own capabilities, the United States must work with critical Arctic partners such as Canada, Norway, and Denmark. Non-Arctic NATO members such as the United Kingdom and France should also engage with Arctic allies and ensure that their naval forces can contribute to enhancing Arctic security.

This also increases the urgency of adding Sweden and Finland to NATO. Both countries are Arctic powers. Both add significant military capabilities to the alliance in a region of vulnerability. They also have the means and geography to provide important intelligence on Russian activity on or near Novaya Zemlya.

Russia’s suspension of New START participation is the latest in a sequence of events leading to the likely death of the treaty. Russia publically suspended U.S. inspections of Russian sites in August and withdrew from the treaty’s bilateral consultative commission meeting in Cairo in December. On-site verification inspections have been on indefinite hiatus since 2020 due to the Covid-19 pandemic.

Why is Russia taking this step now? The likely reason is that the cost of withdrawal has decreased for Russia while the benefits of testing have become increasingly important. Russia will need to increase its reliance on nuclear weapons to deter either an adversary’s aggression against Russia or an international intervention to support Ukraine. 

Meanwhile, unilateral suspension of or withdrawal from the treaty would likely bring significant condemnation from international actors. Supporters of greater arms control would call for increasing Russia’s isolation. This could harm Russia’s trade and relations with its European neighbors. 

This potential harm has already happened. Russia’s isolation from these states has grown significantly over the course of the war, and trade—especially in oil and gas—has plummeted with Europe. Much of this trade has shifted to China and India, with the potential for future trade growth with both Beijing and New Delhi. Neither has strong support for arms control agreements. China has resisted efforts to bring it into an arms control regime and has interests in expanding its own arsenal. It has also built an increasingly close partnership with Russia. 

India, meanwhile, has been an outspoken critic of the global arms control and nonproliferation regime since its inception in the 1960s. India may also benefit economically from new nuclear testing. Advancements in nuclear weapons technology could spill over into Russia’s civilian nuclear sector, which has been an important partner for India’s small but growing nuclear energy industry.

The death of New START is likely upon us. In its wake is the increasing potential for a new era of Russian nuclear testing. This testing will increase the effectiveness of Russian nuclear weapons, become a tool for coercive diplomacy, and lead to greater militarization in the Arctic. Russia may also expand its nuclear arsenal. But the strategic and political impacts of doing so will likely be less than the impacts of nuclear testing. The United States has a large stockpile of non-deployed nuclear weapons that could match Russian nuclear expansion for some time. And this expansion will be limited by financial and resource constraints, especially as conventional losses increase the cost of replacing materiel.