Russian President Vladimir Putin’s invasion of Ukraine brings the highest risk of nuclear conflict between Russia and the NATO alliance in over 40 years. The reckless decisions of one man, supported obediently by a handful of military and security officials, imperil the world.

It is not the first time that dictators have done such things. Over the centuries, national leaders and their defense and security officials have periodically launched military blunders based on miscalculation or messianic egos—think of Napoleon, or Hitler, to name just two examples.

Putin has now done so in Ukraine. It is precisely because of such human error that nuclear deterrence is ultimately an unsustainable, dead-end strategy for international peace and security. It is also why a negotiated end to war in Ukraine must include a “nuclear off-ramp” that leads to a clear reduction of the role of nuclear weapons in international statecraft—especially in the architecture of European security.

An outcome like this is indeed possible, that relies upon a new security architecture in Europe that is based on a small number of major pillars. First and foremost, NATO and Russia must agree that “nuclear war can never be won, and must never be fought”—as they agreed as recently as two months before the Ukraine invasion began (White House 2022). The strategic doctrines and nuclear deployments of both parties must reflect this conviction, and include pledges not to use nuclear weapons first.

Another important action would be to ease Russia’s security concerns regarding the intentions of the NATO alliance, by withdrawing back to US territory all US nuclear weapons based in the NATO alliance countries of Italy, Turkey, Belgium, the Netherlands, and Germany. Consistent with this, the United States must promise that it will not deploy nuclear weapons to any current or future NATO member. This step would not weaken NATO security and would ease an important, long-standing worry of Moscow’s.

Correspondingly, Russia should agree to remove its more numerous non-strategic nuclear forces to central storage away from Europe and never deploy them to certain regions near Russia’s borders such as Kaliningrad, Crimea, eastern Ukraine, Belarus, Moldova, or any portions of Georgia under its control.

In addition, Russia, NATO, and the United States should seek to replace the former treaty on Intermediate-Range Nuclear Forces (INF)—which the Trump Administration withdrew from in August of 2019—with new, verifiable bans on short- and medium- range cruise and ballistic missiles in the European region. (Short- and medium- range refers to missiles with ranges between 310 and 3,400 miles.)

Finally, the two sides need to agree on limitations of conventional forces and force exercises in the wake of the disaster in Ukraine. This step may take addition time to negotiate but is essential to avoid future European conflicts.

An elevated risk of nuclear war

Ominously, the chance that Russia could resort to the use of nuclear weapons in this conflict is real and growing. This is due to an alarming alignment of realities on the battlefield and in the minds of Putin and his generals—who have both the authority and the capability to employ Russia’s nuclear weapons.

Just before sending his forces into Ukraine, Putin made implicit threats of nuclear use against any nation that might “interfere” with his “special military operation” (Friedman 2022). Putin warned that NATO or US intervention would be answered with “consequences such as you have never seen in your entire history.” Making these nuclear threats more explicit, on February 27, 2022, Putin ordered his Defense Minister and Chief of the General Staff to put Russia’s nuclear deterrent forces in a “special regime of combat duty,” possibly referring to increasing the readiness of nuclear forces for use (Ogilvie-White 2022).

Bolstering the credibility of his nuclear brinksmanship, Putin declared in his speech justifying the invasion that the possibility of Ukraine joining western alliances “is not only a very real threat to our interests, but to the very existence of our state and to its sovereignty” (Holloway 2020). In essence, Putin has proclaimed that Russia’s stakes in the outcome of the Ukraine conflict are indivisible from the risk of the destruction of Russia itself—an important development, as this rhetoric directly aligns with one of the circumstances identified in Russia’s official military doctrine for justifying the potential use of nuclear weapons. Russia’s doctrine, adopted in the year 2000, states that the Russian Federation retains the right to use nuclear weapons if it is attacked with nuclear weapons—and it also specifically states that nuclear use is permitted “in the case of aggression against the Russian Federation with the use of conventional weapons, when the very existence of the state is put under threat.” (Italics mine.)

Unfortunately, there is yet another element of Russian military doctrine that could possibly be used as a fig leaf to support using nuclear weapons to shape the outcome of the Ukraine conflict. The doctrine allows for the option of using nuclear weapons to end a war on terms more favorable to Russia if it found itself beginning to lose a large conventional war. The idea is that in a conventional war where Russia’s stakes are viewed to be higher than those of its opponent, and which Russia has begun to lose on the battlefield, Russia could freeze the status quo and limit its losses by using a small number of low-yield, high-precision nuclear weapons. The opponent would then be so stunned and concerned with escalation that it would accept a settlement to the conflict rather than further defeating Russian forces—a strategy which has been termed “escalate to de-escalate.” Unfortunately, the current situation in Ukraine very much resembles this scenario, and Putin knows it.

Putin’s willingness to make these nuclear threats in alignment with Russia’s stated military doctrine—indeed, his utterance in this speech is almost word-for-word identical to the formal published doctrine—is unprecedented in recklessness and irrationality, especially as it comes at a time when Russia has neither suffered a nuclear attack nor is its “very existence” endangered. Russian nuclear alert levels have not been raised in 40 years. It was likely crafted intentionally by Putin in hopes of blackmailing the United States, NATO, and the European Union into inaction by threatening nuclear war. The immense level of risk in this strategy is such that observers are rightly questioning Putin’s state of mind.

Tragically, when nations rely on theories of nuclear deterrence as the foundation for their national security, they cannot escape the kind of dangers embodied in Putin’s threats. In such situations, the chances of nuclear use can increase rapidly, even if national decisionmakers take steps to reduce them. The friction of war inevitably increases the vulnerability of nuclear command and control systems to human and mechanical error. What would happen now if Russian radars mistakenly indicated that a US nuclear attack was underway, or a US missile blows up in its silo? These scenarios are not idle speculation; both events have happened in the past. (Schlosser 2013)

Precisely because the nuclear threat is so real, the nuclear signaling and diplomacy displayed by President Biden, NATO, and the US military leadership has been directly opposite to that of Vladimir Putin. For example, President Biden has publicly declined to increase the alert status of US nuclear forces. America also postponed a long-planned test launch of a nuclear-capable intercontinental ballistic missile that could be viewed as provocative by Russia during the conflict in Ukraine. Nor have British or French political or military leaders, as the two other members of NATO possessing national nuclear arsenals, rattled their nuclear swords in response to Russia’s aggression.

We must all be thankful that America and NATO have acted in strict consistency with the belief that nuclear weapons stand apart, that they are weapons of last resort, and should never be brandished during limited wars. This prudent and cautionary behavior is essential to preventing nuclear war. Unfortunately, such behavior is never guaranteed from any national leader possessing nuclear weapons. All the caution in the world cannot stop Vladimir Putin from ordering the use of nuclear weapons if he so chooses. This highlights the fact that the decision to use nuclear weapons should never be in the hands of one official head of state, or even a small number of national officials (Gronlund, Wright, and Fetter 2021).

Re-building security in Europe

The Ukraine conflict has spotlighted like no other the unacceptably high risk of nuclear war between the United States/NATO and Russia. Responsibility for the deterioration of political relations between these players over the past 30 years must be assigned to both sides. Unfortunately, as political relations worsened, the multilateral diplomatic and legal mechanisms formalizing shared understandings of strategic, military, and nuclear matters have unraveled as well. Rebuilding them is a challenging and complex undertaking, requiring commitment and compromise.

Following the end of the Cold War, NATO took bold and positive steps to reduce nuclear risks— including shifting away from reliance on nuclear weapons in its overall defense strategy. NATO drastically reduced its arsenal of non-strategic nuclear weapons in Europe. America also removed all of its non-strategic nuclear arms from surface ships and submarines (Kimball and Reif 2017).

Unfortunately, the alliance followed those positive steps with a series of mistakes in its nuclear strategy that, combined with its acceptance of new member nations from the former Soviet Bloc, created a growing sense of insecurity in Russia. For example, when it released its “Enlargement Study” in September 1995, NATO stated that new members Czech Republic, Hungary, and Poland were expected to support the concept of deterrence and the essential role that nuclear weapons play in NATO strategy. This meant that these countries could be included under NATO’s nuclear umbrella even though no NATO nuclear weapons were deployed to their territories. This policy was extended as more nations joined NATO in 2004, including Latvia, Lithuania, and Estonia—all former members of the Soviet Union.

Moreover, in 1998 NATO rejected calls from members Germany, Canada, and the Netherlands for the alliance to adopt a nuclear “no-first-use” policy.  Both NATO’s 2010 Strategic Concept (NATO 2010) and its 2012 Deterrence and Defence Posture Review (NATO 2012) stated that NATO reserves the right to use nuclear weapons first if necessary, that US nuclear weapons will remain deployed on the territories of several European member states, and that NATO will remain a nuclear alliance for as long as nuclear weapons exist. These developments essentially extended the United States’ and the NATO nuclear umbrella right to Russia’s borders, along with the threat that NATO reserved the right to use nuclear weapons first in a conflict.

Putin has long complained that these developments were unacceptable to Russia. The prospect that Ukraine would someday join NATO and receive US-backed nuclear deterrence against Russia is a major reason Putin invaded Crimea in 2014 and the rest of Ukraine in 2022.

Remove tactical nuclear weapons from Europe

The risk of nuclear war in Ukraine stems from a contest over the rights of Ukraine’s 44 million citizens to choose their own form of government, laws, and relations with other nations. These are rights almost universally acknowledged in international discourse as belonging to all states. Conversely, Putin is claiming that Russia has the right to control the aspirations of Ukraine’s population and he is threatening the world’s 7.7 billion people with nuclear war to back up his claim. In effect, this war could be thought of a personal vendetta for Vladimir Putin, who is threatening the use of nuclear weapons in order to intimidate other states from providing aid to Ukraine.

NATO and the United States must set aside this shocking possibility, and instead concentrate on on the future—more specifically, on what happens once hostilities end. They must make great efforts to place relations with Russia on more stable ground. This requires a new security architecture between the United States, NATO, the European Union, and Russia—one that ensures that nuclear threats are unacceptable and confirms that nuclear weapons are weapons of last resort, whose only legitimate purpose is deterring or responding to direct, large-scale military attacks that threaten the existence of their possessors.

One step in particular might give Russia a face-saving diplomatic accomplishment, partially mollify the consequences of its Ukraine disaster, and reduce future nuclear threats in Europe: NATO could finally agree to remove all US nuclear weapons from member territories, which is a goal that Russia has long sought.

Such weaponry is epitomized in the impending NATO deployment of the B61–Mod12 nuclear smart bomb on F-35 stealth aircraft.

The B61-12 is a tactical nuclear weapon with selectable yield intended to destroy military targets with minimum collateral damage. The warhead has four yield options, ranging from 0.3 kilotons  to 50 kilotons. Plans call for approximately 180 US B-61-Mod12 bombs to be shared by Belgium, Germany, Italy, the Netherlands, and Turkey, beginning this year. Germany in fact just announced (Reuters 2022) that it will buy 35 US-made F-35A fighter jets—opposed to its previously planned purchase of aircraft that would not be certified to carry B-61 nuclear bombs.

Before the Ukraine war, the majority position within NATO was that US nuclear weapons deployed in Europe have only a political role, with NATO’s nuclear deterrence requirements fulfilled by French and British nuclear forces and US nuclear weapons deployed outside Europe. Over the years, political and public opinion in Belgium, the Netherlands, and Germany has generally opposed US nuclear weapons.

For several years, Moscow has stated that if the United States was to withdraw its nuclear arms from European soil, then Russia would be willing to address its own stockpile of an estimated 2,000 tactical nuclear warheads (Fuhrhop, Kühn, and Meier 2020). Moreover, just before its forces attacked Ukraine, Russia’s foreign ministry released a proposed treaty for the United States that would require removing its nuclear weapons from NATO bases. These developments indicate that a broad treaty eliminating both Russian and US nuclear weapons in the European region is possible.

Without such an agreement, the proliferation of tactical nuclear weapons in the region after the war in Ukraine is likely. The US deployment of the B61-12 would proceed as planned. Russia could deploy tactical nuclear forces into areas it controls in Ukraine and also in Belarus. (Soon after the fighting in Ukraine began, Belarus approved a constitutional change that would allow Russian nuclear weapons to be redeployed there [Radio Free Europe 2022]). The re-introduction of nuclear arms to Belarus, and possibly Ukraine, after they were removed 30 years ago would not only increase the chance of nuclear war in Europe, it would also sharply undermine the Nuclear Non-Proliferation Treaty which seeks to stop the spread of nuclear arms globally and eventually eliminate them from national arsenals.

NATO should agree to the removal of US nuclear weapons. In exchange, Russia should agree to decrease its stockpile of approximately 1,000 to 2,000 tactical nuclear warheads and store the remaining weapons in bunkers far from its western border with Europe. It should also pledge never to deploy nuclear weapons to Ukraine—including Crimea and the eastern breakaway republics—or to Kaliningrad or breakaway territories in Georgia and Moldova. Belarus and Kazakhstan must remain non-nuclear weapon states. These proposals are not new, but the war in Ukraine has made them essential to peace and stability in Europe.

New limits on short- and intermediate-range missiles

Russia’s proposals before the war included prohibitions on the deployment of missiles previously outlawed by the Intermediate-Range Nuclear Forces (INF) Treaty. The treaty required the elimination of both ballistic and cruise missiles with ranges between 500 and 5,500 kilometers (310 and 3,418 miles) regardless of whether they carried nuclear or conventional warheads. The United States, citing long-standing Russian violations of the treaty, withdrew from the INF treaty in August 2019 (Bugos 2019). Russia also announced it is no longer bound by the treaty.

Russia has indicated its interest in renewing formal limitations on this category of weapons. Because they can strike deep into the opponent’s territory with little warning time, ballistic and cruise missile with these ranges are particularly destabilizing in Europe. Following the war in Ukraine, Russia is likely to remain open to formal limits on medium- and shorter- range missile systems. This is because, in the absence of such prohibitions, NATO nations such as Poland, Romania, Bulgaria, the Czech Republic, Latvia, Lithuania, and Estonia may indeed deploy missiles with these ranges, either purchased from the United States or another allied nation. There will be an outcry from these nations on NATO’s eastern flank that they need strengthened military capabilities in the wake of Russia’s attempt to destroy Ukrainian independence.

A new agreement could exclude limits on these categories of missiles in the Asian part of Russia and the United States. This caveat would address US complaints that China remains unconstrained in deploying medium- and short- range missiles and consequently would benefit if the United States is banned from even possessing such systems. A new treaty prohibiting land-based missiles in the European region would be most effective if it addresses shorter-range systems such as Russia’s Iskander missile launchers that can fire both ballistic and cruise missiles. The Iskander system has been used against Ukraine and is deployed in Western Russia, Russia’s Kaliningrad exclave, Belarus, North Ossetia in Georgia, and Armenia.

Nuclear no-first-use pledge

Ever since Vladimir Putin asserted that Russia saw the highest stakes in the war in Ukraine—and because Russia and the United States reserve the right to use nuclear weapons first in a conflict—the world has been on edge. The war in Ukraine should cause a fundamental re-thinking of the role of nuclear weapons, highlighting the immense risks inherent in the strategy of deterrence, and demonstrating their uselessness for actually fighting wars. Unfortunately, another lesson taken by nations that do not have nuclear weapons and do not enjoy firm security guarantees from nuclear-armed states is that they might need nuclear arms to deter aggression. Ukrainians will certainly wonder whether Russia would have invaded their territory had they continued to possess nuclear arms, as Ukraine did immediately after the breakup of the Soviet Union.

In order to reduce the threat of nuclear use in limited conflicts and mitigate the continued risks of nuclear proliferation globally, the five, nuclear-armed permanent members, or “P5,” of the UN Security Council (the United States, Russia, China, the United Kingdom, and France) should revise their declared national security strategies to include clear pledges that they will never be the first to use nuclear weapons. China already has such a declared policy, and similar pledges by the rest of the P5 would make their policies more consistent with the view that the sole purpose of nuclear weapons is to deter nuclear attack.

Limits on conventional military forces

The fact that Russia was able to mass nearly 200,000 troops on Ukraine’s borders without triggering both a violation of international law and pre-set military force posture responses in NATO, demonstrates the need for formal, legally-binding limits on levels of conventional forces and force exercises in Europe and western Russia. The last major agreement on limiting and monitoring such forces, called the Treaty on Conventional Forces in Europe (CFE), signed by 22 nations in 1990, expired in 2007 when Russia suspended its participation.

The war in Ukraine has revealed Russian weaknesses in conventional military operations. The professional military class in Russia will understand the implications of this for the balance of forces in Europe. In addition to failing to achieve its war aims against the comparatively much smaller and less well-equipped Ukrainian army, Russia will now have to contend with strengthened NATO forces that have been moved closer to Russia and will likely remain there for several years at minimum. Russia also faces the negative consequences of prolonged multilateral sanctions for its economy and defense industries.

This new reality can motivate Russia to enter negotiations on conventional force limitation and monitoring agreements. The objective of such talks should be to establish a balance of forces in Europe at minimal levels, limit the size and duration of major training exercises, and provide for mutual verification of treaty provisions through monitoring and inspections.

There is, however, no guarantee that progress can be made rapidly on conventional forces limitations between Russia, Ukraine, and NATO. First, the disposition of forces at the end of hostilities is unknown and will be the first problem to address. A negotiated cease-fire could leave 150,000 Russian troops and their equipment on the territory of Ukraine. But Russia may agree to withdraw a great majority of these forces in exchange for NATO forces on its eastern flank returning to pre-conflict levels. Negotiating truly stabilizing limits on conventional forces over the longer term will take sustained political will on both sides and a willingness by Russia to forego threatening to change the boundaries of sovereign states by force. It is unclear if a Russian government led by Vladimir Putin can agree to these conditions.

A path forward

The Ukraine conflict reminds us just how dangerous the threat of nuclear war in Europe remains 30 years after the end of the Cold War. It also makes clear that there is a fundamental disagreement between Russia and NATO on the status of Ukraine and other European areas of the former Soviet Union and the legitimacy of using military force to shape that status. Establishing new security understandings and mechanisms to build stable security architecture in Europe will take years.

As soon as a cease-fire in Ukraine is reached, NATO should indicate it is willing to remove US nuclear weapons from Europe in exchange for similar Russian reductions and rearward movement of its non-strategic nuclear forces. Near-term agreement on such steps can reduce the threat of nuclear war. They can also set the stage for negotiations on replacing the INF treaty with a new agreement banning intermediate-  and short- range offensive missiles in the European region. Revising declared military strategy to assert that nuclear arms are weapons of last resort and that neither NATO, the United States, nor Russia will use them first in a conflict would reinforce the benefit of missile and nuclear arms reductions.

Without eventual agreement on the level and disposition of conventional forces, the steps outlined above cannot bring enduring stability in Europe. Success in achieving such agreement seems remote, even if an end to fighting in Ukraine can be negotiated. Herculean diplomatic efforts must be made to overcome the distrust that exists between NATO and Russia, and provide more transparent military-to-military relations at reduced force levels. The alternative is a series of frozen conflicts that can erupt at any time along the borders of the former Soviet Union and prolonged, wasteful, and hazardous military competition.