On September 25, Russian president Vladimir Putin provided insights into changes to Russia’s long-anticipated new nuclear doctrine. He indicated that the nuclear mission was being “expanded” and outlined numerous changes from the previous 2020 doctrine. While the doctrine itself has yet to be released as a policy document, Putin’s comments come after hints from his allies about the Kremlin’s thinking on nuclear issues—that there exists the “basis for a nuclear war”—and from Russian officials, such as Deputy Foreign Minister Sergey Ryabkov, who said in early September that Russia was updating its doctrine in response to Western intervention in the escalating war in Ukraine. It will be important to check Putin’s comments against the doctrine document, whenever it is released. But the timing of Putin’s remarks and the changes he announced indicate Russia is increasing its reliance on nuclear weapons in an attempt to deter Western assistance to Ukraine. The purpose of the new doctrine may be not only deterrence but also an attempt to divide European allies on the basis of how much risk they are willing to accept in supporting Ukraine. A Pattern of Nuclear Saber-Rattling Russia’s most recent nuclear doctrine was the 2020 Basic Principles of State Policy of the Russian Federation on Nuclear Deterrence. It pointed to the importance of nuclear deterrence for ensuring Russia’s “sovereignty and territorial integrity.” It also outlined four conditions under which Russia would use nuclear weapons, to include receiving data about an incoming ballistic missile attack; use of nuclear weapons or another weapon of mass destruction against Russia or its allies; attacks on Russian nuclear command, control, and communications infrastructure; and attacks against Russia with conventional weapons that threatened “the very existence” of the Russian state. The doctrine also pointed to the importance of nuclear weapons to prevent “an escalation of military actions and their termination on conditions that are acceptable for the Russian Federation and/or its allies.” This language, along with discourse in Russian defense circles, suggested Russia would rely on its nuclear weapons not only when the survival of the state is at risk, but also when it is already engaged in a conventional fight and seeking to coerce or bully another state into submission. Since its illegal invasion on February 24, 2022, Russia has implemented this playbook in Ukraine. A CSIS study earlier this year found over 200 cases of Russian leaders referring to nuclear weapons in the context of the war in Ukraine. As the conflict on the ground has escalated, so have Russian nuclear threats. In the past six months alone, Russia has conducted military drills involving tactical nuclear weapons with Belarus, and in an unprecedented move, announced the drills to the Russian public. Additionally, Russia withdrew its ratification of the Comprehensive Nuclear-Test-Ban Treaty in 2023, and Ryabkov said earlier this month that Russia is “fully ready” to resume testing if necessary. Russia is normalizing a dangerous nuclear discourse. International responses to Russia’s nuclear saber-rattling have been mixed. While it is believed that Chinese and Indian leaders pressured Putin to refrain from escalation and potential nuclear use in October 2022, many states have been conflicted about publicly condemning Russia’s actions and threats. Many countries in the Global South have expressed broad condemnation of nuclear tensions without calling out Russia explicitly because of alliances with Moscow. It is possible, therefore, that Russia believes it can continue to make nuclear threats with minimal consequences. Russia’s strategy of relying on nuclear threats to deter Western support for Ukraine is particularly pertinent at this moment in the war. Ukrainian forces have been seizing territory inside Russia itself, along with attacking Russia with 144 drones in early September. This week Ukrainian president Volodymyr Zelensky is visiting the United States to pitch his “victory plan” to U.S. decisionmakers, which would entail “quick and concrete steps by our strategic partners—from now until the end of December,” according to Zelensky, and act as a “bridge” to a round of peace talks. But one of the most influential decisions about the war will come not from Kyiv but from Washington as to whether or not Ukraine launches long-range strikes into Russia, such as targeting airfields and production facilities, with American-made weapons. The question of long-range strikes has prompted debate among NATO allies because of the potential risks of escalation and Russian retaliation. What’s New in Russia’s Nuclear Doctrine? In this context of uncertainty about U.S. and NATO support for Ukraine’s next steps, Putin announced changes to the nuclear doctrine. His remarks highlighted that nuclear weapons were an “extreme measure to protect the country’s sovereignty,” but acknowledged that this “expanded” the deterrence mission of Russia’s nuclear arsenal. Putin said, “The conditions for Russia’s transition to the use of nuclear weapons are also clearly fixed.” Assuming Putin’s comments essentially equate to (or accurately represent) the new Russian nuclear doctrine, at least four main differences between the new doctrine and the 2020 version are identifiable. First, rather than referring to “allies” more broadly, the doctrine explicitly mentions Belarus as protected by the Russian nuclear umbrella. He stated, “We reserve the right to use nuclear weapons in the event of aggression against Russia and Belarus as a member of the Union State.” Arguably, Belarus has been covered by Russia’s extended deterrence for decades as part of the Collective Security Treaty Organization; however, Russia has not explicitly mentioned Belarus in its doctrine until now. This could be emblematic of an increasingly close strategic relationship between Moscow and Minsk, as Russia deployed tactical nuclear weapons to Belarus this year. Second, Russia’s 2020 doctrine explained nuclear weapons could be used against conventional attacks “when the very existence of the state is in jeopardy” and said nuclear deterrence “guarantees protection of national sovereignty and territorial integrity of the State.” Putin’s explanation of the new doctrine, however, drops this phrase, instead stating nuclear weapons could be used against a “critical threat to our sovereignty,” a much broader and more ambiguous phrasing, which would affirm suspicions of Russia’s “escalate to de-escalate” strategy. What this suggests is that Putin is lowering the threshold for potential nuclear use while also increasing ambiguity about when nuclear weapons would be used. It signals a willingness to take greater risks in the war in Ukraine and attempts to sow uncertainty into the minds of Russia’s adversaries. Third, the new doctrine holds responsible third-party states that support conventional attacks on Russia, even if they are not the ones conducting the attacks. Putin said, “The updated version of the document proposes that aggression against Russia by any non-nuclear-weapon state, but with the participation or support of a nuclear-weapon state, should be considered as a joint attack on the Russian Federation.” This change, in particular, seems clearly targeted at NATO members arming Ukraine in the ongoing war. Finally, the previous doctrine said nuclear weapons could be used in the event of data confirming an incoming ballistic missile attack, but the new version also expands the nature of incoming attacks that could warrant nuclear use to include “aerospace attack,” such as “aircraft, missiles, and drones.” This, also, seems clearly tailored to the ongoing war in Ukraine and an attempt to increase the stakes for NATO members supporting Ukraine. The main takeaway from these changes in Russia’s doctrine is that they are targeted at NATO in the context of Ukraine, signaling an expansion of circumstances under which Russia would use nuclear weapons and a greater willingness to escalate the ongoing war. Russia’s Attempt to Up the Stakes These changes in nuclear doctrine suggest that Russia is doubling down on its strategy of relying on nuclear weapons for coercive purposes in the ongoing war in Ukraine. Arguably, this approach has a mixed track record. On the one hand, Russian nuclear threats may have delayed Western military support for Ukraine in the early days of the war, following Putin’s threat to inflict consequences “such as you have never seen in your entire history” if the West interfered with the special military operation. On the other hand, ongoing nuclear threats have not deterred expanding NATO support for Ukraine, along with the expansion of the alliance itself. One example of failed threats was Russia’s 2022 warnings that supplying Ukraine with missiles would cross a “red line”: U.S. allies have faced no repercussions for doing so. If anything, these statements have led to unwanted consequences from Moscow’s perspective, such as the expansion of NATO. Given the mixed—at best—track record, why would Russia double down on its strategy of nuclear bullying, and why now? One possibility is that Russia doesn’t see its nuclear threats as unsuccessful and has instead focused on the nominal gains of nuclear bullying. This might include slowing the delivery of key capabilities to Ukraine, including tanks, fighter jets, and missiles. Another possibility is that Russia thinks past attempts at deterrence failed because they weren’t “big” enough. This is a particularly dangerous consideration because at some point there will be internal and reputational pressure to uphold a redline. A final possibility, and the one that seems most likely, is that Putin thinks the context has changed so perhaps the threats will be more successful under different conditions. Putin could perceive that NATO is more divided now over the issue of long-range strikes than earlier in the war and see it as an opportunity to sow further divisions among the allies and undermine external support for Ukraine. The key for the United States and NATO allies is to hold the course in remaining united in support for Ukraine and NATO’s nuclear mission. To be sure, the risk of nuclear use in Ukraine should be taken seriously; however, Putin’s attempt to highlight an asymmetry of stakes should not undermine NATO’s position. At the Washington summit, NATO members agreed, “The fundamental purpose of NATO’s nuclear capability is to preserve peace, prevent coercion and deter aggression. As long as nuclear weapons exist, NATO will remain a nuclear alliance.” Additionally, the United States has conducted a “strategy-driven review” of the U.S. nuclear posture and modernization plans, and Biden administration officials have confirmed that, in the absence of arms control and if U.S. adversaries stay on their current trajectories, the U.S. nuclear arsenal may be “necessary but not sufficient,” and there is a growing debate about options for potentially changing or expanding the U.S. nuclear arsenal. But it is not only the United States and other NATO members that have an opportunity to restrain Russia’s nuclear bullying. Many of Russia’s partners are members of the Treaty on the Prohibition of Nuclear Weapons, which bans threats of nuclear use. Given their positions on nuclear deterrence and disarmament, they may be better positioned to condemn Russia’s ongoing nuclear threats, either publicly or privately, and encourage Moscow to engage in arms control dialogues. Barring any change in the costs Moscow feels for this type of nuclear rhetoric, it is likely to continue on the current trajectory. The new nuclear doctrine is just the latest attempt at nuclear bullying against Ukraine, and deterring and dividing Western support for Kyiv. Heather Williams is director of the Project on Nuclear Issues and senior fellow with the International Security Program at the Center for Strategic and International Studies in Washington, D.C.