Russia’s Nuclear Option Hangs Over Ukraine and NATO

As NATO leaders convene for a pivotal summit, there’s one major security threat that allied leaders prefer to talk about only in broad, circumspect terms: the threat of nuclear war.

Russia’s full-scale invasion of Ukraine has thrust the risk of a nuclear showdown between Moscow and the West back into the spotlight. While all allied countries agree the risk of Russia escalating the conflict in Ukraine remains low, there’s a growing gap between the United States and some other allies as to when and how that risk could increase, according to interviews with nearly a dozen current and former NATO officials and security experts.

The nuclear question is an existential one for the alliance, one that’s driven Washington’s calculations on what military aid to send to Ukraine and when, and it has also influenced the debate on when and how to allow Ukraine to join the military alliance as a full-fledged member. That debate is playing out at the NATO summit in Vilnius, Lithuania, this week, where NATO leaders agreed to “extend an invitation to Ukraine to join the alliance when allies agree and conditions are met.” 

Some U.S. and other NATO defense officials believe there could be an increased risk of Russia launching a limited nuclear strike with a low-yield tactical nuclear weapon to stave off a major battlefield defeat if its forces look to be on the verge of a rout, or if Ukraine appears poised to capture Crimea and large swaths of occupied territory in southern and eastern Ukraine. Others say that Russian President Vladimir Putin’s nuclear saber-rattling won’t go further than that, and bowing to such threats will only embolden Russia to use such “nuclear blackmail” in the future.

At the same time, Ukrainian and Western officials also fear that Russia could mount an attack on Ukraine’s Zaporizhzhia nuclear power plant to attempt to trigger a major radiological event, irrespective of whether it launches a nuclear strike—though it’s unclear how successful those efforts would be.

That debate over Russia’s threshold for going nuclear in Ukraine sharpened after Putin announced Russia would deploy tactical nuclear weapons to neighboring Belarus, the first time that Moscow will dispatch part of its nuclear arsenal outside of Russia’s borders since the end of the Cold War. Back in Moscow, meanwhile, prominent Russian scholars and officials are engaging in an unusually public debate about the merits of using tactical nuclear weapons if the war in Ukraine continues to drag on. Many NATO leaders dismissed the move of nuclear weapons to Belarus as posturing aimed at unnerving NATO. Other officials and experts warned that some NATO allies missed or dismissed signs of Russian military escalation before, most notably in the run-up to the invasion of Ukraine last February, and needed to take these signals from Moscow more seriously.

Top Biden administration officials, meanwhile, say they take the nuclear threat very seriously but aren’t letting it bind U.S. support for Ukraine. “I think that there are two caricatures in the discourse about the threat of the use of tactical nuclear weapons,” U.S. National Security Advisor Jake Sullivan told a small group of reporters ahead of the NATO summit in Vilnius. “One caricature is the Biden administration is paralyzed by the nuclear threat and therefore won’t support Ukraine sufficiently. I think that is nonsense.”

“The other caricature is this nuclear threat is complete nonsense. Don’t worry about it at all. It’s to be completely discounted. That also is wrong,” Sullivan said. “It is a threat. It is a real threat. It’s one we need to take seriously. And it is one that does evolve with changing conditions on the battlefield.”

Other major voices in NATO say the prospect of Russia actually launching nuclear weapons, even lower-yield tactical nuclear weapons, remains too slim to factor into support for Ukraine. “I’m not concerned about the nuclear issue. I don’t think Putin dares to push the nuclear button,” Anders Fogh Rasmussen, the former NATO secretary-general and Danish prime minister, said in an interview. “The response from the United States and its allies would be very harsh and the rest of the world would turn its back to Russia, including China and India. So I think an attempt to use nuclear weapons would be the end of the Putin regime.”

At its summit in Vilnius, top agenda items include Sweden’s accession to NATO after months of diplomatic negotiations with Turkey, the debate over Ukraine’s NATO membership, and the rolling out of large-scale regional defense plans akin to the alliance’s Cold War playbook. Much about those regional defense plans will remain secret, and NATO isn’t likely to reveal how its allies’ nuclear weapons factor into those plans in detail. 

However, alliance leaders signaled that changes were afoot in modernizing its nuclear plans, albeit couched in stilted and formal diplomatic language, that signify how the alliance is re-assessing its nuclear deterrence in ways unseen since the days of the Cold War. “NATO will take all necessary steps to ensure the credibility, effectiveness, safety and security of the nuclear deterrent mission,” the alliance leaders said in a lengthy joint communique issued at the summit. “This includes continuing to modernise NATO’s nuclear capability and updating planning to increase flexibility and adaptability of the alliance’s nuclear forces, while exercising strong political control at all times.”

NATO has only one publicly disclosed nuclear military exercise per year, dubbed “Steadfast Noon,” which it disclosed for the first time in 2019. Other than that, the prospect of expanding nuclear exercises, or merging military exercises involving conventional and nuclear forces, remains “incredibly taboo” within the alliance, said William Alberque, an arms control expert with the International Institute for Strategic Studies and former NATO official.

While the nuclear debate plays out in NATO circles, there’s another nuclear debate playing out on the other side of the war among Russian foreign-policy experts and elites, including some now overtly calling for nuclear strikes on Ukraine that could signify a shift in Moscow’s thinking on when and how to deploy tactical nuclear weapons. Those debates center on the premise that Putin’s unprovoked invasion of Ukraine is critical to the survival of Russia, a common talking point from top Russian officials and state media outlets that is sharply disputed by an overwhelming majority of the international community. 

“It is necessary to arouse the instinct of self-preservation that the West has lost,” Sergei Karaganov, a prominent Russian political scientist, wrote in the research journal Russia in Global Affairs last month, in a piece entitled “A Difficult but Necessary Decision” justifying the possible use of nuclear weapons against Ukraine. That piece kick-started a fierce and—for an autocratic country as tightly controlled as Russia—unusually open public debate about Moscow using nuclear weapons in Ukraine to halt the West’s support for that country. 

“Morally, this is a terrible choice as we will use God’s weapon, thus dooming ourselves to grave spiritual losses. But if we do not do this, not only Russia can die, but most likely the entire human civilization will cease to exist,” Karaganov wrote. 

Other Russian scholars pushed back, but not because of the incalculable devastation a nuclear attack would have, but rather because it would alienate Russia from other world powers outside the West. “Russia will turn into a toxic asset for Beijing, New Delhi, Riyadh, and many other capitals. No one will accept our arguments that we had no other choice, that we were forced to make such a decision,” Ivan Timofeev, another scholar, wrote in response. 

Dmitry Trenin, once considered by many in Washington to be the most respected and influential Russian foreign-policy expert in Western circles, has also advocated for Russia to escalate its nuclear threats over Ukraine. “The ‘nuclear bullet’ must necessarily and demonstratively be put into the ‘revolver drum’ the U.S. leadership is recklessly playing with. To paraphrase a now-deceased American statesman, we can say: Why do we need nuclear weapons if we refuse to use them in the face of an existential threat?” Trenin wrote. 

Ultimately, Russia’s decision to deploy nuclear weapons won’t come down to elites debating in Moscow, but rather one man: Putin. Bonnie Jenkins, the top U.S. arms control envoy, told reporters in a briefing on Tuesday that the United States and NATO took nuclear threats from Putin seriously and the alliance’s resolve and unity in support of Ukraine served as a major deterrent against Russia. 

But, she added, “the fact is we don’t know how Putin is thinking about what he’s going to do next.”