If Russia were to use a tactical nuclear weapon in Ukraine it would, as CIA Director William Burns put it in public remarks last week, “change the world in a flash.” It might not, however, according to several experts, result in the direct military involvement of the west or a broader nuclear war.
That is not to say that such an attack would not produce devastating consequences beyond those related to the attack itself. There are a wide range of options that NATO would consider—many of which would produce lasting, disastrous consequences for Russia. Further, there is a clear sense among current and former U.S. government officials that Western leaders' disinclination to take the bait and trigger a global war would and should be seen as a sign of strength. Finally, for all these reasons, such an act of Russian desperation is likely to be yet another huge miscalculation on the part of Vladimir Putin.
Although nuclear weapons have not been used since the American attacks on Hiroshima and Nagasaki in the late summer of 1945, concerns about their use are higher than they have been in decades. CIA Director Burns, in remarks at the Georgia Institute of Technology last Thursday, said, “Given the potential desperation of President Putin and the Russian leadership…none of us can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons.” On Friday, Ukrainian President Volodomyr Zelenskyy echoed this warning saying that the international community should be concerned about Russian use of nuclear or chemical weapons, saying, “We should… not be afraid but be ready.”
Senior U.S. officials with whom I spoke emphasized that Burns was not basing his comments on any new intelligence or other evidence that Russia was preparing to use nuclear weapons, but rather on a prudent analysis of Russia’s situation. They mentioned that Russian doctrine had a “lower threshold” for the use of nuclear weapons than other nations, but that it was “still pretty high.” According to that doctrine, there were two kinds of events that would warrant consideration of the use of nuclear weapons. One was if the Russian military was facing a massive defeat that threatened its ability to further defend its country. The other was if there was a direct threat to the regime in Moscow.
A U.S. official who is closely tracking these matters noted that top Russian officials have been explicit in pointing out that the threat from events in Ukraine was not “existential.” This is seen as a possible signal that nuclear use was yet to be warranted under the guidelines described above. He added, “Nothing we’ve seen suggests they’re at the precipice” of taking such action.
U.S. officials also emphasized that in such circumstances, it would be expected that the first use of a nuclear weapon would be as a “warning shot,” likely the detonation of a device in the upper atmosphere. Whether Russia chooses such an approach or another, however, U.S. officials are confident NATO has multiple options via which to inflict high costs on the Russians without “transgressing” as the Russians would have done.
Should Russia use nuclear weapons of any sort on NATO forces or territory, the result would, of course, be swift and severe. A conventional attack on such forces, for example, would trigger a direct confrontation that it is believed the Russians very much want to avoid.
NATO currently has more troops in regions bordering Ukraine than Russia has in Ukraine. NATO’s military is much better equipped and trained than Russia’s. Ukraine has administered many crushing defeats on the Russians. It is unlikely that Putin—even at the moment of his greatest arrogance or frustration—would willingly undertake a battle with a force so clearly superior to his. As one senior U.S. national security official put it to me, “A fight would not be close.”
General Wesley Clark, who served as Supreme Allied Commander in Europe, said with regard to the use of a tactical nuclear weapon, “We don’t have any comparable weapons. If Putin uses a tactical nuclear weapon against Ukraine forces, it’s just another weapon. We provide more assistance. If he uses it against a city, we still respond with more assistance. We would also bring against him more condemnation and sanctions. If he strikes a NATO country, then we have to respond militarily. But still without using a nuclear weapon. Only if there are a series of nuclear strikes would I recommend a nuclear response.”
Jon Wolfsthal, who served as senior director for arms control and non-proliferation on the Obama administration’s National Security Council said, “We should not say precisely what a response to nuke use should be, but make clear it would change the entire nature of the conflict. Being too specific allows Putin to judge risk vs reward. It would be much different from chemical weapons use. Chemical weapons are horrible, but limited. Nukes are exponentially different…I don’t see how we ever accept or live with a Putin who does that. It would lead to war crime charges versus Putin and all who carried out the order. He would never leave the country again.”
Wolfsthal concluded, “As for whether we use nukes, I think the answer is no. Ukraine is not NATO. In the event of a first use, we step up military support even more and make clear any use of nukes against NATO would mean a massive expansion of the conflict.”
This view is echoed by other nuclear weapons experts, such as the Quincy Institute’s Joe Cirincione who said, “U.S. and NATO conventional forces are sufficient to devastate the Russian invasion force, without resorting to nuclear use. I believe that this is also the response that most military commanders would prefer. There are just too many uncertainties involved in using nuclear weapons. Plus, of course, the long-term environmental consequences. One reason military commanders don’t favor using nuclear weapons is that they contaminate the battlefield and make land that they’re trying to defend unusable for decades. Think Chernobyl.”
Cirincione adds that he is skeptical of arguments that minimize the consequences of the use of a “small” nuclear weapon.
“As far as I know,” he says, “The smallest warhead they have in their arsenal is a 10 kiloton warhead, or about two-thirds Hiroshima size. This would be many times more destructive than the largest conventional weapons in our arsenal. Further, Russian doctrine doesn’t dictate the size of the warhead. If they’re using it to cause a shock and try to force the west and the Ukrainian forces to immediately sue for peace then they are going to want to use a large enough warhead. There’s no reason to think that they will go small. Exactly the opposite.”
Former Estonian President Toomas Hendrik-Ilves worries that the use of a nuclear weapon would rattle many European leaders. “A whole slew of them might immediately sue for peace, cave to the Russians. Germany would likely lead the crew,” the former president told me.
However, Hendrik-Ilves adds: “To use a nuclear weapon breaks the ultimate taboo. There is no moral distinction to be made between a ‘tactical nuke’ and a strategic one. It would be a complete game-changer for the world. We should signal publicly and privately starting now that it would mean complete and total isolation. All embassies shut. All visas canceled. All Russian properties confiscated.”
Former U.S. Ambassador to NATO Douglas Lute, a former U.S. Army lieutenant general, echoed the importance of communicating clearly the consequences of any such attack now. Lute says, “As for advance notice, we should make clear that the response would include unprecedented military, economic, cyber, and diplomatic measures, but not be more precise. Ambiguity could enhance deterrence and complicate Russian attempts to avoid our response by navigating around specific if-then conditions.”
Should military-grade chemical weapons be used, a question would be whether military or civilians were targeted. Use of WMDs against civilian areas would produce “substantially different” responses from those against the military. Although, in both cases, once the WMD threshold is crossed, targeted NATO strikes on particular military units or facilities would no longer be off-the-table. More likely, however, would be a major ratcheting up of sanctions. This would likely include the immediate complete halting of purchases of Russian oil and gas, and the provision to Ukraine of much more advanced weapons systems including missiles that could strike well into Russian territory.
If Russia were to use a nuclear weapon or chemical weapons against a civilian target or targets, the response would be “much more severe.” In this or some of the more serious cases described above, another possibility would be making all sanctions against Russia permanent. There is a belief among U.S. officials that Putin thinks the end of the war will bring him a “get out of jail” card, a reprieve from international pressure. Use of WMDs would likely reduce the odds of that substantially.
Says Lute, “Crossing the nuclear threshold, no matter the target, should cause a precise conventional attack on the origin of the Russian attack, even if it is on Russian territory, which it likely would be. If the origin cannot be determined, then an attack on a similar capability (Iskander short range ballistic missile (SRBM), cruise missile, submarine, bomber site) should be conducted. Further, the US along with others should launch air strikes in support of Ukrainian ground forces with the aim of defeating the Russian forces in Ukraine, the proximate cause of the nuclear strike. A complete economic blockade of Russia should be emplaced immediately, enforced by NATO naval and air forces.”
Former U.S. Ambassador to NATO Ivo Daalder goes further, saying that if WMDs are used by Russia, “NATO should be willing to intervene directly and defend Ukraine. The stakes change dramatically if they use a nuke or actual chemical weapons [as opposed to industrial chemicals]. Whether to communicate this publicly is less important than that they (a) agree and (b) tell Putin directly (as happened I am told regarding chemical weapons in the conversations [U.S. National Security Adviser Jake] Sullivan and [his Russian counterpart Nikolai] Patrushev had last month.”
Dr. Kori Schake, who directs defense and foreign policy studies at the American Enterprise Institute and who has served in significant Defense Department, NSC, and State Department posts advised, “What the U.S. should threaten in advance, and actually do if the Russians are preparing to use nuclear or chemical weapons in Ukraine is to (a) make clear that doing so would trigger direct U.S. military retaliation against Russia, and that retaliation would be directed at the Russian leadership and any policy officials or military officers the transmit or carry out the order; (b) pursue those officials until all have been either killed or tried for war crimes; (c) share first privately with Ukraine, then NATO allies, and then publicly the intelligence about Russian preparations and plans; (d) interdict—that is, attack—the units involved to prevent the use.”
It is important to reiterate that in none of the above cases (except for the use of multiple nuclear weapons) is a nuclear exchange considered a possibility by current or recent top officials and experts. As one senior U.S. official said to me, “We’ve been very careful to maintain our ‘Vegas rules’ discipline. That is, we very much are trying to limit the consequences of this war so that what happens in Ukraine stays in Ukraine.” He noted the courage and bravery of the Ukrainian people and underscored that protecting and preserving their lives and their country is also of paramount interest, but that it was in no one’s interest for this conflict to spread further.
As Daalder notes, the core goal of the Atlantic Alliance should be to “demonstrate that using nuclear weapon[s] conveys neither a military nor a strategic advantage to Russia and will only result in a devastating U.S. and NATO conventional response.”
General Clark sees an opportunity to translate this point into a broader message that “It is the policy of the United States to ensure that no aggressor can succeed. We must make clear to Putin that he will not win. We then must do everything necessary to assist Ukraine to eject Russian forces from Donbas and the south and then let diplomats argue over Crimea.”
