Special Report: Assessing Putin’s Implicit Nuclear Threats After Annexation

Mason Clark, Katherine Lawlor, and Kateryna Stepanenko

September 30, 12:45pm ET

Russian President Vladimir Putin did not threaten an immediate nuclear attack to halt the Ukrainian counteroffensives into Russian-occupied Ukraine during his speech announcing Russia’s illegal annexation of Ukrainian territory. Putin announced Russia’s illegal annexation of Ukraine’s Donetsk, Luhansk, Kherson, and Zaporizhia oblasts on September 30 even as Ukrainian forces encircled Russian troops in the key city of Lyman, Luhansk Oblast, immediately demonstrating that Russia will struggle to hold the territory it claims to have annexed. Putin likely intends annexation to freeze the war along the current frontlines and allow time for Russian mobilization to reconstitute Russian forces. The annexation of parts of four Ukrainian oblasts does not signify that Putin has abandoned his stated objective of destroying the Ukrainian state for a lesser goal. As ISW assessed in May, if Putin’s annexation of occupied Ukraine stabilizes the conflict along new front lines, “the Kremlin could reconstitute its forces and renew its invasion of Ukraine in the coming years, this time from a position of greater strength and territorial advantage.”[1]

Putin’s annexation speech made several general references to nuclear use that are consistent with his past language on the subject, avoiding making the direct threats that would be highly likely to precede nuclear use. Putin alluded to Russia’s willingness to use “all available means” to defend claimed Russian territory, a common Kremlin talking point. Putin stated that “the US is the only country in the world that twice used nuclear weapons, destroying the Japanese cities of Hiroshima and Nagasaki. Incidentally, they created a precedent.” Putin stretched his historical allusions, stating that the United States and the United Kingdom demonstratively and without a military need destroyed many German cities during World War II with the “sole goal, just like in the case of nuclear bombardments in Japan, to scare our country and the entire world,” attempting to portray Western states as the true aggressor. Putin did not directly articulate any new red lines or overtly threaten to use a nuclear weapon against Ukraine if Ukrainian counteroffensives continue.

Putin is attempting to force Kyiv to the negotiating table by annexing Russian-occupied territory and threatening nuclear use.[2] He is following the trajectory that ISW forecasted he might on May 13. As ISW wrote at the time: “A Russian annexation would seek to present Kyiv with a fait accompli that precludes negotiations on territorial boundaries even for a ceasefire by asserting that Russia will not discuss the status of (illegally annexed through military conquest) Russian territory—the argument the Kremlin has used regarding Crimea since 2014.” Predictably, Putin demanded that Ukraine return to negotiations in his September 30 speech announcing annexation and precluded any discussion of returning illegally annexed Ukrainian territory to Kyiv’s control: “We call on the Kyiv regime to immediately cease all fire and hostilities and end the war it initiated in 2014 and return to the negotiations table. We are ready for it and have said that several times. But the decision of the people in Donetsk, Luhansk, Zaporizhia, and Kherson we will not negotiate. This choice has been made and Russia will not betray it.”

Putin’s call for negotiations and implicit nuclear threats are aimed at both Ukraine and the West; he likely incorrectly assesses that his nuclear brinksmanship will lead the United States and its allies to pressure Ukraine to negotiate. As ISW wrote in May: “The Kremlin could threaten to use nuclear weapons against a Ukrainian counteroffensive into annexed territory to deter the ongoing Western military aid that would enable such a counteroffensive.” However, Ukraine and its international backers have made clear that they will not accept negotiations at gunpoint and will not renounce Ukraine’s sovereign right to its territories. As Ukrainian Foreign Minister Dmytro Kuleba wrote on September 20, “Ukraine has every right to liberate its territories and will keep liberating them whatever Russia has to say.”[3] Where does this leave Putin, then, and what are the actual prospects for the Russian use of nuclear weapons?

ISW cannot forecast the point at which Putin would decide to use nuclear weapons. Such a decision would be inherently personal, but Putin’s stated red lines for nuclear weapon use have already been crossed in this war several times over without any Russian nuclear escalation. Reported Ukrainian cross-border raids into Belgorod Oblast and strikes against Russian-occupied Crimea could arguably meet the stated Russian nuclear use threshold of “aggression against the Russian Federation with the use of conventional weapons when the very existence of the state is in jeopardy.”[4] Putin framed Ukraine as posing an existential threat to Russian sovereignty repeatedly at the start of his full-scale invasion—a phrase that meets that stated threshold: “For our country, it is a matter of life and death, a matter of our historical future as a nation. … It is not only a very real threat to our interests but to the very existence of our state and to its sovereignty. It is the red line which we have spoken about on numerous occasions,” he said on February 24.[5] Formal Russian nuclear doctrine is evidently not a deciding factor for Putin, who has reportedly been micromanaging this war down to the operational level.[6]

Putin has set in motion two major means short of nuclear use through which he will try to achieve his objectives: partial mobilization to replace Russian losses, and wintertime energy pressures on Europe to deter European support. He likely intends Russia’s ongoing mobilization to stabilize Russian positions and enable the temporary freezing of the conflict. He is unlikely to succeed; rushing thousands of untrained and unmotivated Russian men to the front will not meaningfully increase Russian combat power, particularly in places like western Luhansk oblast where the Ukrainian counteroffensives are making significant progress. Putin intends his second approach, curtailing natural gas exports to Europe, to fracture the Western consensus around supporting Ukraine and limit Western military aid to Ukrainian forces. This too is unlikely to succeed; Europe is in for a cold and difficult winter, yet the leaders of NATO and non-NATO European states have not faltered in their support for Ukrainian sovereignty and may increase that support in light of Russia’s illegal annexation even in the face of economic costs.[7] European states are actively finding alternatives to Russian energy and will likely be far more prepared by winter 2023.[8] It is difficult to assess what indicators Putin will use to evaluate the success of either effort. But both will take considerable time to bear fruit or to demonstrably fail, time Putin will likely take before considering a nuclear escalation.

Putin would likely need to use multiple tactical nuclear weapons in Ukraine to achieve his desired operational effect—freezing the front lines and halting Ukrainian counteroffensives. But the operational effect would need to outweigh the potentially very high costs of possible NATO retaliation. Putin might try a nuclear terror attack against one or more major Ukrainian population centers or critical infrastructure in hopes of shocking Ukraine into surrender or the West into cutting off aid to Ukraine.  Such attacks would be highly unlikely to force Ukraine or the West to surrender, however, and would be tremendous gambles of the sort that Putin has historically refused to take. Ukraine’s government and people have repeatedly demonstrated their will to continue fighting, and the West would find it very challenging simply to surrender in the face of such horrific acts because of the precedent such surrender would set. Putin is therefore far more likely to use nuclear weapons to change the operational environment, if he uses them at all. We assess Putin has two main tactical nuclear weapon use options: striking key Ukrainian ground lines of communication nodes and command centers to paralyze Ukrainian offensive operations, and/or striking major Ukrainian force concentrations near the line of contact. A single nuclear weapon would not be decisive against either of these target sets. Putin would likely need to use several tactical nuclear weapons across Ukraine to achieve significant effects and disrupt Ukraine’s ability to conduct counteroffensives. The scale of nuclear use likely required would raise the risks of Western retaliation, likely increasing the potential costs Putin would have to weigh against the likely temporary benefits the strikes themselves might provide.

Russian nuclear use would therefore be a massive gamble for limited gains that would not achieve Putin’s stated war aims. At best, Russian nuclear use would freeze the front lines in their current positions and enable the Kremlin to preserve its currently occupied territory in Ukraine. Russian nuclear use would not enable Russian offensives to capture the entirety of Ukraine (the Kremlin’s original objective for their February 2022 invasion). Russian military doctrine calls for the Russian Armed Forces to be able to effectively fight on a nuclear battlefield, and the “correct” doctrinal use of tactical nuclear weapons would involve tactical nuclear strikes to punch holes in Ukrainian lines, enabling Russian mechanized units to conduct an immediate attack through the targeted area and drive deep into Ukrainian rear areas.[9] The degraded, hodgepodge Russian forces currently operating in Ukraine cannot currently conduct effective offensive operations even in a non-nuclear environment. They will be flatly unable to operate on a nuclear battlefield. DNR/LNR proxy units, Wagner Group fighters, BARS reservist units, and the depleted remnants of the Russian conventional units that actually exercised fighting on a nuclear battlefield in annual exercises—not to mention newly mobilized replacements shipped to the front lines with less than a week of training—will not have the equipment, training, and morale necessary to conduct offensive operations following nuclear use. NATO is additionally likely to respond to Russian nuclear weapon use in Ukraine with conventional strikes on Russian positions there.  Russian use of multiple weapons (which would be required to achieve decisive operational effects) would only increase the likelihood and scale of a Western conventional response.

The more confident Putin is that nuclear use will not achieve decisive effects but will draw direct Western conventional military intervention in the conflict, the less likely he is to conduct a nuclear attack. 

[1] https://www.understandingwar.org/backgrounder/russian-annexation-occupied-ukraine-putin%E2%80%99s-unacceptable-%E2%80%9C-ramp%E2%80%9D

[2] https://www.understandingwar.org/backgrounder/russian-annexation-occupied-ukraine-putin%E2%80%99s-unacceptable-%E2%80%9C-ramp%E2%80%9D

[3] https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-september-20

[4] https://rusemb dot org dot uk/press/2029#:~:text=25.,with%20the%20Collective%20Security%20Treaty; https://globalsecurityreview.com/nuclear-de-escalation-russias-deterrence-strategy/

[5] https://www.nytimes.com/2022/02/24/world/europe/putin-ukraine-speech.html?smid=tw-share;

[6] https://www.theguardian.com/world/2022/may/16/putin-involved-russia-ukraine-war-western-sources

[7] https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-september-20

[8] https://www.npr.org/2022/09/20/1124008571/russias-attempt-to-use-energy-to-pressure-europe-could-backfire

[9] https://www.armyupress.army.mil/portals/7/hot%20spots/documents/russia/2017-07-the-russian-way-of-war-grau-bartles.pdf.