Since Russia’s invasion of Ukraine, no concept in International Relations has gained greater prominence in public debate than deterrence. The conflict has generated widespread distrust and suspicion in international politics, driving European-wide rearmament, and preparing for worst-case scenarios. Former neutral countries like Finland chose to pick a side. The Baltics and Poland, especially, are leading the effort of fulfilling the NATO pledge of spending 5% of GDP on defence, while Germany just adopted new conscription laws to fulfil NATO requirements. They all share a common objective: deterrence, which is translated into massive procurement programs. Germany, for instance, aims to expand its armoured fleet from 1,000 to 3,000 Main Battle Tanks (MBTs) and Infantry Fighting Vehicles (IFVs), while Poland contracted in 2022 with South Korea to acquire nearly 1,000 K2 MBTs. Yet, what strategic logic underpins these capabilities? Why prioritise heavy land forces over alternatives such as substantial stockpiles of long-range, precision-strike systems? Similarly, despite recurring debates over a French nuclear umbrella for the European continent, why has the idea of a nuclear option not been pursued more decisively, especially given the current context of American disengagement from NATO?
As the title suggests, this article offers perspectives on these questions through the conceptual lens of deterrence, drawing on lessons from Ukraine and explaining why current approaches to deterrence may prove less effective than intended. However, it is important to examine the deterrence literature and history to fully understand the foundation of the argument made.
Deterrence, Strategy, Denial, and Punishment
Deterrence comes along with a range of familiar buzzwords: credibility, threat, capability, costs, and benefits. In his study, Morgan (2003, pp. 1-8) presents a broad spectrum of definitions, ranging from deterrence as the act of dissuading an opponent from taking a particular action by threatening sanctions if the forbidden act should be performed (which would include non-military means like economic sanctions) to narrower military conceptualisations, where the enemy is discouraged from using military force through the threat or application of military means. He highlights the importance of distinguishing between deterrence theory, which concerns the theory’s principles and assumptions, and deterrence strategies actors pursue to deter a potential aggressor, which are concerned with (military) postures, communications, and the explicit and implicit threats they generate. For example, while the US military footprint is spread across the globe and German military power is concentrated primarily at home and in its immediate periphery, these postures stem from the same theoretical principles but pursue different strategies and objectives.
Throughout most of history, if military buildup was not pursued in the aim of conquest, deterrence was mostly concerned with denying an adversary territorial gains. Given technological constraints, it was simply not possible to inflict large-scale costs beyond the actual battlefield. Consequently, the military’s aim focused on territorial control, rendering geopolitics effectively synonymous with military affairs, just as strategy was (or is) inseparable from questions of territory and force. The concept of denying the potential aggressor its objectives has become known as deterrence by denial. The invention of the aircraft and its military adaptation into airpower, particularly during World War II (WWII), provided policymakers with a new means of deterring before or coercing during war: the prospect of punishment.[1] The underlying logic marked a departure from earlier approaches. Even if an attack could not be prevented and damage was incurred, the aggressor would in turn face even greater costs through retaliatory punishment by the defender, for instance, by means of strategic bombing campaigns. Large-scale aerial bombings in Europe during WWII largely followed this punishment logic. But deterrence (and especially punishment) did not fully emerge as a theoretical concept until the advent of the atomic bomb. It was the prospect of total annihilation, particularly after the United States lost its nuclear monopoly with the Soviet Union’s acquisition of nuclear weapons, that fundamentally changed the logic behind the purpose of armed forces. As Brodie (1946) noted, the chief purpose of the military shifted from winning wars to preventing, or deterring, them. Nuclear weapons became the ultimate instrument of punishment, especially when states acquired a secure second-strike capability, resulting in Mutually Assured Destruction (MAD). These developments marked a profound transition: war ceased to be a viable instrument of policy as described by Clausewitz (1989 [1832]), and instead became something to be avoided. The literature on deterrence, such as Snyder (1961), associated deterrence by denial strategies mostly with conventional capabilities, while punishment became almost synonymous with strategic nuclear weapons. Subsequent technological advances, most notably the development of long-range precision missile systems, introduced an additional conventional layer to punishment-based deterrence options. The war in Ukraine today demonstrates how relatively cheap drones enable mass punishment instruments, with some drones flying several hundred, even thousand kilometres. 
The distinction between denial and punishment is not always clear-cut, however. Long-range fires, for example, can be employed to strike enemy forces on the defender’s own territory, thereby denying an enemy its objective to occupy land. Conversely, operations involving conventional land-forces, such as Ukraine’s Kursk Offensive in August 2024, may be designed less to seize territory than to impose costs on the adversary. Much like a tank can serve both offense and defence, military capabilities often blur the line between punishment and denial, depending on the purpose of their employment and on the pursued strategic intent.
Strategic Intent in Europe and Lessons from Ukraine
According to this logic, strategy rests on intent. The intent in Europe is to deny the Russian Armed Forces the ability to conquer and hold NATO territory. For this reason, European countries are rearming their militaries with large numbers of tanks, air-defences, and artillery firing platforms, all while ramping up their manpower. This purchase list speaks a language of denial. It is easy to sell to the public why land forces and air-defence systems are important.
Particularly interesting, however, is the shopping (and deployment) list of punishment instruments. In his Zeitenwende speech, Olaf Scholz announced that Germany intended to buy F-35 jets to secure its role in nuclear sharing with the United States and in NATO nuclear planning. The Scholz government later also announced that the United States would station long- and mid-range missiles like Tomahawks and (still in development) hypersonic missiles in Germany starting in 2026, which sparked huge public and academic debate over escalation management and even war mongering. This is no surprise. A punishment and retaliation-focused deterrence strategy goes against the long-held pacifist sentiments in Europe, always aiming to seek reconciliation rather than making bold moves and risking escalation. Escalation has become the top-tier Angst of European capitals, as argued in a previous article of mine.[2] Therefore, punishment, escalation, and risk were outsourced to the United States, resulting in a significant strategic IQ gap. With the United States signalling disengagement from the European theatre, however, this outsourcing might not be possible anymore. But it is even more complicated:
During an interview with German talk master Markus Lanz, Zelensky underlined the importance of security guarantees. While avoiding the question of European troops on Ukrainian soil, he stressed the importance of providing Ukraine with massive amounts of long and mid-range fire capabilities as a credible security package. Why? Because Ukraine has learned the hard way two simple truths: first, it is impossible to determine when denial ends, and conflict is resolved. Let’s say, in a hypothetical scenario, Ukraine can push Russian forces back to the pre 2022 lines of contact. Will this be the end of the war, or will Russia simply continue to fight in pursuit of its pre-war aims? The same is true for Europe writ large. If Russia attacks Poland and is repelled from pre-war Polish borders, does Europe think that the war will be terminated? Second, denial strategies raise difficult questions about attrition and offer the aggressor (in this case, Russia) the potential to outsource its aggression to politically inconsequential parts of society. After the Kremlin’s partial mobilisation, Russian force composition consisted mostly of far-east ethnic minorities, convicts, lower social classes, and mercenaries incentivised by high signup bonuses and graveyard money. This continues to enable the Kremlin to throw more people in without suffering any political consequences, it seems. This is exactly why Ukraine continues to ramp up its punishment capability by targeting Russian oil infrastructure, defence-industry and logistical hubs in Russia itself. It believes that by making the war felt by ordinary (and politically significant) Russians, it can turn the political tide in Moscow’s disfavour. Because, as a “smaller” state, Ukraine depends on denial strategies, it desperately (and I think impressively) demonstrates that it can indeed punish Russia’s illegal attack beyond the battlefield. The picture Russia seeks to draw is that it can drag the war on forever, shifting the blame for “prolonging” the war to Ukraine’s dependency on denial strategies as a weaker state. What does this mean for European deterrence?
Implications for European Deterrence Postures
In a recent article, Fabian Hoffmann argues that Europe needs to embrace punishment strategies because it cannot keep up with interceptor missile production at the speed of Russian missile production. In this article, I make the case that the problem facing denial-centred strategies is deeper and more structural.
The elephant in the room when talking about punishment is always nuclear weapons. There are reasoned debates about a European nuclear umbrella under French leadership. This is particularly important in the context of the US strategic conventional withdrawal from Europe. Even though US policymakers assure that Washington’s nuclear umbrella will remain, the growing interconnectedness of conventional and nuclear capabilities (for example, with Tomahawks soon to be stationed in Germany that can carry both nuclear and conventional warheads), it would be naïve to think that the credibility of the nuclear deterrent will not suffer due to conventional withdrawal. Europe must come to terms with the implications of these developments and, if it chooses to pursue a European nuclear option, support such efforts with substantially stronger political will.
The second elephant in the room is the current domestic political instability on the continent. Macron must balance European ambitions with growing nationalist sentiment in France; Russia-friendly AfD is significantly constraining Chancellor Merz in Germany; and Keir Starmer faces Nigel Farage in the UK. If selling these domestic audiences rearmament has already proven difficult, pitching them a deeper strategic logic towards greater assertion in international politics, which is always tied to questions of money and burden-sharing, is considered to further shift the political balance in their favour. I cannot offer a definitive solution to these problems, but I am convinced that clearly and accessibly communicating the nature of the threat Europe faces is essential to fostering public understanding of why new ways of thinking are required in a fundamentally changing world.
Ultimately, the debate Europe must confront is not about capabilities on its own, but about the political logic that gives those capabilities strategic meaning. A posture centred predominantly on denial may reassure domestic audiences, yet it risks signalling that Europe is still reluctant to assume primary, comprehensive responsibility for the continent’s defence. Ukraine’s experience demonstrates that without punishment options, denial alone can lock defenders into protracted wars of attrition that favor ruthless and authoritarian adversaries. Denial can become a politically convenient substitute for addressing the harder strategic questions about escalation, cost imposition, and war termination that many governments in Europe have outsourced to the United States since the end of WWII. Credible deterrence rests on solid strategic logic, not on budgets and shopping lists alone.
A preliminary version of this article was first published in the author’s personal Substrack Blog.
[1] It is important to draw a theoretical distinction here: during WWII, aerial bombing campaigns largely followed a coercive aim by punishment, seeking to force concessions or cause moral collapse by targeting the enemy’s population centres.
[2] There is an important nuance here. My perspective is highly German-centric, shaped by my personal and academic background in Germany. Some European states are significantly less risk-averse, which is why they are considered as potential strategic leaders in the defence of the continent.
