Introduction
President Donald Trump’s attempt to end the war in Ukraine continues, but for how much longer? He has recently stated that his patience is wearing thin. Even if a meaningful ceasefire materialises, the extent to which the U.S. might provide security guarantees is still unknown. One thing that appears to be clear is that European nations will be taking the lead in any peacekeeping force used to enforce whatever peace deal might be negotiated, and that NATO security guarantees, such as Article 5, may not extend to this force. This poses a unique risk when it comes to potential nuclear escalation should further conflict occur in the future. A lack of NATO security guarantees may leave a European peacekeeping force in Ukraine vulnerable to nuclear strike. A brief hypothetical scenario may help demonstrate this.
The year is 2029…
President Donald Trump is coming towards the end of his second term as president, and it looks like a more pro-Ukraine candidate is going to be elected. Russia, having seen a significant easing of sanctions as part of a peace deal, has reconstituted and improved its military capability and learned its mistakes from the 2022 invasion. Worried by the possibility that the U.S. will soon be more likely to intervene to defend Ukraine, President Putin decides to act. After conducting a series of false flag operations – designed to look like Ukrainian aggression – Russia launches another invasion, banking on the European peacekeeping force being unwilling to take significant casualties, and the U.S. not intervening.
However, Russia still suffers from significant command and control issues, and the European nations have also improved their own military capabilities. Russian forces make little progress and suffer heavy casualties – European casualties remain surprisingly limited. In Moscow, the prospect of another failed military operation sees pressure mounting on Putin – talks of a coup swirl. Putin decides to make good on a threat that was now falling on deaf ears. Russia launches a SS-26 Stone SSM with a 10-kiloton tactical warhead.
Deliberately used in a less kinetic area of the front, targeting reconnaissance forces proving routes for a potential advance, the military impact of the detonation was limited, as was intended by Russia; however, the strategic impact was huge. With the U.S. still unwilling to provide material support, despite overwhelming condemnation of Russia’s actions, Europe and Ukraine struggle to come up with a response, with Russia threatening further use of its tactical nuclear weapons.
Sheltering under a Anglo-French umbrella?
Anyone with a vague knowledge of the Ukraine conflict could probably poke holes in the scenario above, but it illustrates a point. A peacekeeping force in Ukraine may face the risk of nuclear escalation by Russia. The U.K. and France may offer to have Ukraine under their ‘nuclear umbrella’; however, with only strategic weapons at their disposal, a nuclear response to a tactical nuclear strike would be grossly disproportionate. Given this, any force in Ukraine needs to ensure it can deal with a nuclear strike in a conventional way. This will include ensuring maneuver forces can continue to operate in a nuclear environment, as the employment of tactical nuclear weapons by Russia will likely, at least in part, be designed to limit freedom of movement.
Fighting in a nuclear environment
A nuclear strike would require a military force to deal with a number of challenges. The blast itself will almost certainly lead to casualties, just like a conventional munition. The thermal radiation of even a 10-kiloton warhead is likely to cause anything flammable within hundreds of meters to ignite and cause severe burns to those in the vicinity.
Ionizing radiation will soon see cases of radiation sickness beginning to appear, which, even if not fatal, will require specialized medical treatment. Residual radiation from unfissioned weapon debris and radioactive fission products will be carried by winds to areas on the battlefield not near the initial blast and again poses a risk of radiation sickness. Intense radiation can also damage optical and mechanical systems, and, depending on the size and type of detonation, the electromagnetic pulse from a nuclear device could also damage electrical equipment.
Measures can be taken to mitigate these risks. Personnel can be issued with personal protective equipment and potassium iodide. Infrastructure, both physical and technical, can be hardened. Post-blast, while decontamination is not really possible, medical treatments can be used, but they require medical supervision and the treatment needs to be available in a timely manner.1 Commanders can reduce the exposure of their soldiers with good information as well, using detectors to understand where the radiation risk is greatest, and using personal detectors to see when individuals have been exposed to dangerous levels of radiation.
Are we really ready?
CBRN planning does take place. In February 2025, NATO wargame STEADFAST WOLF brought together over 100 CBRN professionals from NATO and the U.S. to conduct CBRN contingency planning. STEADFAST WOLF was a NATO and American exercise – an organization and nation that are unlikely to take the lead in any Ukrainian peacekeeping force.
Wargaming also does not allow the signals operator, logistician, or medical practitioner the opportunity to really test their skills in a nuclear environment. Whilst Brigadier General Chris A. McKinney, the J5 Deputy Director for Global Partnering, Security Cooperation and Countering Weapons of Mass Destruction at USEUCOM stated that STEADFAST WOLF was ‘not simply focusing on our CBRN Specialized units, but…making sure that our manoeuvre elements as well as our technical support forces are able, if necessary, to defeat and prevail over any adversary in a CBRN contaminated environment’ this was not happening ‘in the field’. Many of us have experienced the unpleasantness of a log run in 4-ROMEO, but very often the CBRN element of any exercise is an afterthought rather than a key learning demand – this must not be the case for a force in Ukraine.
Where is the UK at?
A trained force must also be adequately equipped to fight in a nuclear environment. Whilst access PPE, potassium iodide, and the ability to harden facilities is not a huge logistical task (at least not for the likes of France and the U.K.), specialized units are another matter. The U.K. currently has 28 C-CBRN Engineer Regiment, and Falcon Squadron that conducts CBRN surveillance and reconnaissance. As capable as these units may be, they likely do not have the depth to support a formation deployed to Ukraine as well as the home base. The Defence CBRN Centre also contains the Joint CBRN Medical Faculty. However, given the limited capability of the U.K. to deployable medical facilities to deal with large numbers of casualties, it is unlikely that the required amount of specialized drugs and medical equipment exists to support a U.K. formation fighting in a nuclear environment, even if the training exists.
Why its important
Even if a force in Ukraine did have the ability to respond to nuclear escalation with a measured nuclear response, the ability to operate in a nuclear environment with conventional forces would still be vital to prevent escalation. If a peacekeeping force in Ukraine can credibly operate in a nuclear environment, it would give military commanders and politicians room to maneuver when dealing with a nuclear strike by Russia without having to resort to a nuclear option. It will also have a deterrent effect.
Russia will know that the use of nuclear weapons will lead to widespread condemnation and likely hurt their cause in Ukraine in the long run. The use of such weapons would likely only occur when the political leadership is backed into a corner, and there is a realistic belief that it could turn the tide of military operations. If a force in Ukraine can credibly demonstrate that it can fight through a nuclear strike, it makes the use of one less likely.
Conclusion
The scope of this article is limited. We have not touched on the minutia of the capabilities needed to operate in a nuclear environment – these details are highly technical and to go into them would require a much longer article! However, the wider point remains: a future peacekeeping force in Ukraine must invest time and resources into making itself capable of operating in a nuclear environment, as it is unlikely the allies that will make up that force currently possess the ability to do so.
Reports of Russian soldiers suffering from radiation sickness after digging in around Chernobyl demonstrate Russia’s lack of regard for its soldiers’ welfare in these environments, and that they will fight on regardless. European forces must also fight on, but with the correct training and equipment, so it’s soldiers do not suffer like their Russian counterparts.
(Main picture – British Army Fuchs vehicle – Army image – Crown Copyright)