Russia’s potential use of nuclear weapons early in the Ukraine conflict presents an interesting dilemma. For many analysts, this conflict exemplifies the limits of nuclear deterrence, an issue worth exploring.
Prior to Russia’s invasion of Ukraine, Germany was one of Russia’s closest economic partners. At the outset of the war, Germany was criticized for its hesitant offer to Ukraine of 5,000 military helmets, at a time when other European states, especially the Baltic nations, were offering weapons and heavy military equipment to defend against the Russian invasion.
This hesitancy had two facets. First, the belief that military aid would escalate the war to unmanageable levels. Second, the fear that Russia could easily achieve its military objectives. In such a case, it was unwise for Germany to risk its economic interests, particularly its heavy reliance on Russian natural gas.
However, Germany, later, began supplying weapons and other military aid to Ukraine under domestic and international pressures. Later, Germany even supplied heavy military equipment to Ukraine. As of August 2025, Germany is one of the largest suppliers of military aid, amounting to $47 billion worth. This includes air-defense systems, advanced drones, and heavy artillery. German action illustrates how incremental support erodes Russia’s nuclear red lines.
Incremental Steps Eroding the Threshold
In the Russian conceptualization of deterrence, strategic deterrence (strategicheskoye sderzhivaniye), both nuclear and conventional deterrence merge into one holistically integrated framework. The threat of or actual use of nuclear weapons would deter a conventional attack on Russia, help achieve military objectives, prevent third parties from entering a war, and help de-escalate a war. In the 1990s, when Russia fielded a conventionally inferior armed force, it relied primarily on nuclear deterrence for its security.
However, a nuclear-deterrence-focused security strategy does not consider the erosion of thresholds owing to incremental changes during war (i.e., incremental changes test interwar and intrawar deterrence). After Pakistan became a nuclear power, Pakistan employed sub-threshold tactics (terrorism) against India, assuming that the fear of mutual nuclear vulnerability would prevent India from using kinetic means in retaliation. However, this approach failed when India employed conventional force against Pakistan in 2016, 2019, and, more prominently, in Operation Sindoor (2025). Similarly, Ukraine challenged Russia with its aggressive attacks in response to Russian invasion.
Russia’s updated nuclear doctrine (2024) brought the threshold of nuclear employment to an even lower level than earlier doctrine. This includes “actions by an adversary affecting elements of critically important state or military infrastructure” and “the massive launch […] of air and space attacks means (strategic and tactical aircraft, cruise missiles, unmanned, hypersonic and other aerial vehicles).”
Ukraine’s Operation Spyder Web crossed these “nuclear thresholds” set in the 2024 doctrine. Russia’s numerous threats of tactical nuclear weapons use are not taken seriously by Europe any longer. This creates a stability-instability paradox where “conventional balances also reduce the credibility of nuclear threats precisely because there is a conventional alternative to resorting to nuclear weapons.”
One of the implications of the stability-instability paradox in international relations is that while nuclear weapons create stability at the strategic level by deterring large-scale war between nuclear-armed states, they increase the likelihood of smaller, limited, or conventional conflicts. This is reinforced in the Ukraine conflict, where Russia simply cannot use nuclear weapons to deter third-party military help to Ukraine and Ukraine’s counteroffensives.
Nuclear deterrence has limitations and does not deter incremental or conventional actions of lower yields. The costs associated with utilizing nuclear weapons for deterring incremental erosion of thresholds is unimaginable. It is difficult for parties in a war to agree upon thresholds. Thus, resorting to conventional attacks rather than escalating to nuclear use becomes more likely, even after crossing stated red lines.
States Should Build on That
For that matter, those states looking to augment their defence preparedness should invest in conventional deterrence capabilities that can guarantee security. This goes beyond just building missile and air-defense systems of a high calibre. Conventional deterrence is not merely about weapons to deter an adversary.
Military thinking needs to go beyond just inventing new weapons and focus on military strategy. States need to go beyond a one-size-fits-all understanding of deterrence, where all states subscribe to the same benchmarks, variables, and conceptualization of deterrence, and have a shared sense of it. Situating deterrence within the fold of strategic culture, how a state’s strategic culture shapes deterrence, is more helpful. For instance, in contrast to the denial versus punishment typology, Russia uses the forceful versus non-forceful scheme for deterrence.
States may need to invest in the re-invention of military doctrines, strategy, and thinking to suit current challenges. It is worth studying how adversaries see the concept of deterrence. It confers two advantages. First, it helps one remain prepared for any incremental utilization of force under the fear of mutual destruction. Second, it allows the defender to assess the opponent’s risk-taking appetite and nuclear threshold in a war. This would confer advantages associated with effectively using conventional means.
At the same time, both parties need to be aware of over-extension, where a misguided action can cause a catastrophic nuclear exchange. Since agreeing on the same trigger point is subjective and difficult, states must study the pace, timing, and intensity of the use of non-nuclear forces to effectively achieve objectives without jumping to the nuclear step on an escalatory ladder.
In the end, preventing nuclear war is critical. Thus, understanding thresholds is important. If war is unlikely to end, ensuring it does not escalate to nuclear use should be a top priority.
Anshu Kumar is a Junior Research Fellow at the Centre for Russian & Central Asian Studies, Jawaharlal Nehru University, New Delhi.
