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Military Personnel in Conflicts of Conscience: Between Church Idealism and Political Realism


In 2019, the United States withdrew from the Intermediate-Range Nuclear Forces (INF) Treaty because, as they saw it, Russia had demonstrably violated its terms. This event marked a watershed moment when nuclear deterrence returned with force to the political agenda and into the consciousness of the wider public. Patterns of argument that had seemed consigned to history are being revived. Almost forgotten divisions in political opinion, especially in Germany, are resurfacing. With the termination of the INF Treaty, a key piece of European security architecture has broken away. There seems to be a real danger of a nuclear arms race with Russia. Against this background, the opportunity has been taken within the NATO Alliance to discuss the role of nuclear weapons in defense strategy. This contrasts with the clear position of the Catholic Church, and specifically the pope, who has condemned the strategy of nuclear deterrence as a moral failure. Similarly, the 2007 peace memorandum of the Protestant Church in Germany (Evangelische Kirche in Deutschland, EKD) declared that threatening to use nuclear weapons can no longer be regarded as a legitimate means of self-defense.1 Thus political actors – but especially also members of the military – are in a difficult situation where guidance is urgently needed.

In 2019, the Catholic officers’ study group under the Catholic Military Bishop for the German armed forces examined the topic of “Nuclear deterrence – tensions between ethics and reality”. They sought to investigate the issue from different perspectives. This article describes the group’s detailed discussions.

The initial situation

Nuclear deterrence is back. Of course, it never really went away. But it had faded into the background – and, at least in Germany, had disappeared from public consciousness over the course of recent decades. Those of us of a certain age grew up with the threat of a nuclear apocalypse. In a sense, we learned nuclear strategy from scratch. We knew the NATO MC 14/3 “flexible response” strategy by heart. We had to, or we could never have passed any staff officer course. We were conversant with the NATO Double-Track Decision, and we learned about the peace movement. We remember the big demonstration in the Bonn Hofgarten park, lively debates as youth officers and in civic education classes, the blockade of Mutlangen, and so on. Those were exciting times. But then came the fall of the Berlin Wall, German reunification and the dissolution of the Soviet Union – and by that time at the latest, the subject had disappeared from public awareness. The nuclear stalemate between the superpowers was not an important issue anymore.

Nuclear weapons never went away, but they were no longer part of the strategic discussion. They were an ever fainter shadow in the background, so to speak. When we thought about weapons of mass destruction (WMDs), it was in terms of preventing proliferation. The danger of WMDs ending up in the wrong hands – in those of rogue states and terrorists – was the issue. But because there was a functioning arms control regime, at least between East and West (INF, START, AMB, NPT ...), people thought they were safe. German policymakers focused on defense initiatives, and consequently also supported U.S. President Obama when he called for a nuclear-weapons-free world in Prague in 2009.

NATO, meanwhile, stuck to the concept of nuclear deterrence. And the German federal government at times had great difficulty defending the principle of nuclear sharing against critics of all kinds from the left of the spectrum, but also among the liberals. We recall the efforts of the then foreign minister, Guido Westerwelle, to end the stationing of nuclear weapons at Büchel, which would have meant Germany being excluded from strategic discussions and the nuclear planning process. The fact that the “ideal world” was changing had already become apparent at the end of 2001, when the United States withdrew from the Anti-Ballistic Missile (ABM) Treaty. On August 2, 2019, the U.S. terminated the INF Treaty with the agreement and support of all NATO partners. The INF Treaty banned land-based nuclear intermediate-range missiles (having a range of 500 to 5,500 km). It was one of the most important disarmament treaties between the United States and Russia – a strategic cornerstone, in effect. With the end of the treaty, both countries can build such weapons again without restrictions. A new arms race is feared.

Pandora’s box is open again. We are facing a worrying development, which challenges us as citizens and officers. In our professional capacity, we have to answer to the public. This is a matter of huge proportions: political, strategic, tactical and ethical questions are closely entangled. The deeper in you go, the denser the undergrowth becomes.

The public discussion does not reflect this situation at all. In my opinion, a truly in-depth debate on the complex issues involved in nuclear armaments is taking place in expert circles at most. Yet in regard to the continued existence of mankind, the nuclear threat should be taken at least as seriously as the current crises (COVID-19, climate). It is to be hoped that this important topic will soon again receive the attention it deserves. “The Federal Republic of Germany needs a productive debate on the difficult and complex problems of peacekeeping, which the world is clearly facing today.”2

Discussions in the church are dominated by the dilemma arising from the fact that weapons whose use can never be ethically legitimate are nevertheless supposed to secure peace. The Catholic Church has struggled to find a response that is both in keeping with the Christian teaching tradition – which includes the doctrine of just war – and takes account of the wholly new ethical challenges brought about by advances in weapons technology. In a pastoral letter, the U.S. bishops raised the question of the legitimacy of threatening a nuclear first strike: “May a nation threaten what it may never do? May it possess what it may never use?” Following the Second Vatican Council, a church consensus emerged: the system of deterrence was justifiable only for a transitional period, until efforts to overcome this system would bear fruit. During this period, everything should be done to find humane ways of resolving conflicts (the doctrine of just peace). The pope’s insistent words in this context indicate that this period has come to an end, at least in the teaching of the church.

In light of the discussed tensions arising between ethics and realpolitik when it comes to nuclear deterrence, the “Heidelberg Theses” are once again highly relevant – despite already being 60 years old. They situate the problems of nuclear armament in the wider context of a policy of securing peace and freedom, the legitimacy of nuclear weapons under international law and from an ethical standpoint, the military strategy of deterrence, and conscience counselling for military personnel and citizens. The theses deal with question of whether and to what extent nuclear deterrence can be ethically justifiable. The complementarity concept comes under increasing pressure: deterrence as a valid principle versus rejection of any use of military force. The basic consensus of “staying together under the Gospel” is placed under heavy strain.

Nuclear deterrence – a critical view of the concept

It is worth taking a closer look at the concept of nuclear deterrence. I spent my childhood, youth and the first 17 years of my military career under the all-dominating nuclear umbrella, and I cannot say that it overshadowed my life to any excessive degree. Perhaps I could be accused of naivety for this. Why did the Cold War not end in a nuclear Third World War? Doesn’t that prove the concept of nuclear deterrence worked? Or was it not the case, several times during the Cold War, that we were on the verge of a nuclear confrontation that never happened – as in the Cuban crisis, for example? Was that the blessing of nuclear deterrence? Or was it pure luck, perhaps also favorable circumstances, that we cannot influence or guarantee? From the security policy, military strategy and ethical point of view, it is impossible not to be critical of the concept.

Contrary to widespread beliefs, it is doubtful that deterrence can somehow be organized reliably and predictably. There is also the question of how deterrence can be guaranteed in the post-Cold War era (the “second nuclear age”), if “doomsday weapons” were to fall into the wrong hands. Deterrence inevitably makes us think of the “balance of terror” and “mutually assured destruction”, although the term “balance of terror” probably obscures the problem more than it aids understanding. At first glance, the conditions for successful deterrence do not appear to be overwhelmingly difficult.

There are three necessary conditions:

  1. Someone who is to be deterred must know the threat.
  2. They must believe that the threat is credible.
  3. They must be able and willing rationally to weigh up the potential cost of the threat against the value of continuing their actions.

In short, deterrence requires the capabilities and the will to follow through on the threat, and the other party’s perception that this is the case. The capacity to act rationally is key.

Successful deterrence is therefore a function of capability and credibility. But these conditions are not sufficient, there is more to them, and they are generally ignored. It takes:

  1. Actors who are capable of following a rational decision-making process.
  2. Governments that facilitate the implementation of rational decisions.
  3. Actors who are informed about the interests, plans, values and obligations of their enemies.
  4. Actors who understand and are able to correctly assess military capabilities and the consequences of their actions.

Whether these conditions are met in respect of the persons acting on the global stage is not difficult to answer. I have my doubts, and I am certain that these assumptions would not apply in the event that weapons of mass destruction were to find their way into the hands of non-state actors. It is safe to say that nuclear weapons cannot reliably or with any kind of guarantee ensure deterrence, even though the opposite is often claimed. But we have not found anything better, and we will probably have to keep working with the “deterrence crutch” for a while yet.

Arms control and nuclear deterrence – two sides of the same coin

Questions about the legitimacy of the use of military force are an important part of peace ethics. This is particularly true of weapons whose use could mean the end of human life on earth. Has the time granted to us now definitely run out? Many military personnel who examine their conscience ask themselves these questions. The fact weighs heavily that the major churches have withdrawn legitimacy from nuclear deterrence. Who could shut their eyes to the risks of a nuclear apocalypse? With all the misery, poverty and suffering in the world, who would not take a critical view of the amount of money spent on nuclear weapons? A world without nuclear weapons must be the goal! Most politicians and military personnel who I know are in agreement on this. A nuclear war would place an unbearable load on their conscience. They would carry a heavy burden of guilt. However, we live in a world that unfortunately is not shaped according to our moral and ethical ideals. It is a very “real” and also “evil” world. The Holy See says this about banning nuclear weapons: “In short, to achieve nuclear abolition, we need to resist succumbing to the limits set by political realism.”3 But we – and this particularly applies to us in the military – should face up to reality. That does not mean saying goodbye to our legitimate dreams. A world without nuclear weapons is the goal (as Heiko Maas, the German foreign minister, said on March 5, 2020). The 50th anniversary of the Non-Proliferation Treaty (NPT) reminds us of this. This goal must be persistently pursued.

In keeping with this goal, and in a sign of diminishing confidence in nuclear deterrence, 122 countries signed the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017. This is surely an honorable, morally well founded position. The crucial question, however, is whether this really brings us any closer to the goal of a nuclear-weapons-free world. Does this unilateral step really promote peace and security on our planet, or does it primarily serve to soothe the conscience? This is where idealism and realism collide. For example, the NATO countries reject the TPNW because in their view it does not improve the security of any country. This is true. Would the world be safer if the vast majority of countries signed the TPNW but nuclear weapons “only” remained in the hands of a few – Putin’s Russia, Kim Jong Un’s North Korea, Ayatollah Ali Khameinei’s Iran or Xi Jinping’s China, to name just some? This question should be easy to answer.

Is it not possible to achieve the goal of a safer world by stepping up arms control efforts in accordance with the NPT (Article VI)? If we follow this path, and do not let ourselves be deterred, then isn’t nuclear deterrence – at least on a transitional basis – ethically defensible? My view is: yes, it is! Every member of the military should interrogate their own conscience on this issue. No-one, not even democratic consensus, can take this moral duty off their shoulders. Democratic consensus is not infallible. “For the moral identity of man is decided in obedience to conscience.”4 Perhaps the belief that the defense of freedom also justifies nuclear deterrence will help. A quote by Konrad Adenauer springs to mind: “Peace without freedom is not peace”. So military personnel must have a firm desire to bring peace. Let us remember the four cardinal virtues. I believe that part of the virtue of prudence is not to confuse the journey with the destination. Arms control and disarmament based on nuclear deterrence is the way – a world without nuclear weapons is the goal. The road is rocky and setbacks are numerous. Lots of people are losing patience. Who could blame them? But still we should continue unwavering on the path. We are united in the goal.

Arms control and disarmament – the order of the day

Admittedly, the conditions for far-reaching arms control agreements are not favorable. We are seeing an erosion of the rules-based, liberal, multilateral order. The competition between systems that we are witnessing is also being played out in the nuclear field. Nuclear weapons serve as a means of power for actors to assert their own interests. In this environment, interest in arms control and disarmament is waning. One key element of arms control (the INF Treaty) has already been dropped, and others such as the New Strategic Arms Reduction Treaty (New START) and even the NPT appear to be in danger. Nuclear weapons are still being developed. Proliferation is anything but contained. The number of nuclear powers has “officially” increased from six to nine (India, Pakistan, North Korea). Other states are striving to acquire nuclear weapons. The Joint Comprehensive Plan of Action (JCPOA) – commonly known as the Iran nuclear deal – was a great success of Western diplomacy, but the United States withdrew from it. This increases the danger of nuclear escalation in the Middle East. On March 5, 2020, Rafael Grossi, Director General of the International Atomic Energy Agency (IAEA), expressed his serious concern that Iran was denying IAEA inspectors access to suspect facilities and had far exceeded the limits on the enrichment of uranium set by the 2015 agreement. Not good news – so what should be done?

First of all, it is to be welcomed that Germany is taking the initiative and doing everything it can to strengthen the NPT as the basis of nuclear arms control. German foreign minister Heiko Maas said: “We want to break the nuclear disarmament logjam. The Non-Proliferation Treaty is in acute danger if we do not invest more political capital and make the treaty fit for the future!” The 16 countries involved in the Stockholm Initiative are firmly committed to making real progress on nuclear disarmament. They also want to diminish the role of nuclear weapons in security and defense policies, and prevent a new arms race. Furthermore, they aim to encourage the United States and Russia to extend New START and engage in talks on its possible expansion, thus contributing to strategic stability. It is also important to revive the recently terminated INF Treaty, with the inclusion of China. There are very real reasons why the U.S. and Russia have lost interest in the INF Treaty. It applies only to them, but not to other powers that have nuclear warheads and intermediate-range missiles: China, India, Iran, North Korea, Pakistan. Why should Putin and Trump just look on while others acquire weapons that are forbidden to them, but which shift regional balances of power? In general, it is important to reduce the incentives for states to acquire nuclear weapons as a means of power and self-assertion. The fate of Gaddafi, who was overthrown and killed eight years after renouncing his secret nuclear weapons program, is certainly in the minds of authoritarian rulers. It is hardly likely to increase their willingness to renounce nuclear weapons (North Korea, Iran). For this reason, the policy of maximum pressure pursued by the U.S. administration must be viewed very critically. If anything, the current Iran crisis is evidence of the end of liberal interventionism and the strategy of regime change. A prudent policy of incentives, of sticks and carrots, leads to better success in disarmament and conflict resolution. Here too, in practical policy terms realism proves superior to idealism, however well intentioned. The first task now is to rescue or revive the existing or recently dissolved arms control agreements: the INF Treaty to include China, the NPT and New START.

Deterrence – a necessary “evil”

It is no longer possible to avoid the question of what Germany’s position is with regard to the future of its security through nuclear deterrence – and not only since the United States and Russia declared their withdrawal from the INF Treaty. A question mark can also be placed over whether the United States under President Trump can be relied on to assist Germany on mutually acceptable terms. The protection of the allies is referred to as “extended deterrence”, which conversely means there is an original deterrence reserved for securing one’s own existence. How much is “extended deterrence” worth under the new conditions? In this context, the French president’s offer is interesting. Firstly, interested European countries could start a dialog on deterrence issues, and secondly, Paris could declare a stronger European role for its national deterrent. This is surely a good initiative for strengthening the European pillar in NATO. But is it enough?

Germany would be well advised to con­tinue its commitment to nuclear sharing in NATO, whose protective umbrella is an essential element of European security for us. There is no substitute for this. “Germany is under the NATO nuclear umbrella, which is provided primarily by the United States.” (German defense minister Annegret Kramp-Karrenbauer, February 10, 2020.) Germany can only secure peace in freedom as part of the transatlantic community of values. This is also a profoundly ethical question. All calls to renounce nuclear sharing harm Germany’s security interests. We have an interest in participating in the Alliance’s nuclear strategy, including via our seat in the Nuclear Planning Group. There can be no nuclear German Sonderweg or “special path”.

For our security, credible defense and deterrence within the NATO framework is and remains essential. It must consist of a balanced mix of nuclear and conventional capabilities. This integrated approach to deterrence is often overlooked. The lack of conventional capabilities tends to increase the risk of nuclear weapons being used, which today is extremely low. Or how did the Alliance intend to counter possible Russian aggression against the Baltic states (comparable to that against Crimea and eastern Ukraine) if it could not be prevented by conventional means? Isn’t Putin’s motive in stationing intermediate-range weapons precisely to deter NATO and drive a wedge into the Alliance? The Alliance’s Eastern European states rely on us. It is a question of Alliance solidarity. In this context, the foreign ministers of the Stockholm Initiative made an alarming demand (point 11): “Nuclear-Weapon States to address increasing entanglement of conventional and nuclear systems and to take measures to reverse such development.” But if you say A, you also have to say B conventionally, in other words strengthen conventional capabilities. That is why the Alliance’s efforts to enhance operational readiness and response capacity should be welcomed. This includes the “4 x 30” program, under which by 2020 a total of 30 battalions on land, 30 squadrons in the air and 30 warships at sea should be ready for action within 30 days. 

NATO’s “Defender 2020” exercise, which was conducted for the first time this year (but only to a limited extent, due to the corona pandemic), also serves the goal of increasing response capacity and demonstrating Alliance solidarity.

It is worth noting that in this context as well, Russia so far has been unable to divide the Alliance. On August 2, 2019, the Alliance clearly backed the United States’ decision to withdraw from the INF Treaty, thereby showing unity. NATO wants to respond this year to the Russian stationing of nuclear-capable Russian cruise missiles in Europe. There are plans to station air defense and missile defense systems, as well as strengthen conventional capabilities and increase alert and response capabilities. NATO’s response is therefore defensive, since there are no plans to station new land-based nuclear missiles in Europe. The Alliance is quite deliberately not responding symmetrically but instead allowing room for nuclear arms control and disarmament.

A critical view should also be taken of the first of the Stockholm Initiative’s “stepping stones”: “Nuclear-Weapon States to acknowledge the need to ensure that nuclear weapons will never be used again [...].” This demand undermines nuclear deterrence and brings us immediately to an aporia. Deterrence is impossible without being credible. However, we should critically oppose the idea that smaller nuclear weapons make it possible to wage a nuclear war. What they actually do is lower the threshold for their use. This is why the program to modernize the United States’ nuclear arsenal announced in the U.S. Nuclear Posture Review of February 2018 is rather worrying – particularly the acquisition of low-yield nuclear warheads.

It is time to reflect on (currently lacking) arms control approaches, and especially on the dilemmas involved in concrete nuclear deployment planning and the question of escalation control. A new debate on the Alliance’s nuclear doctrine would seem necessary. Germany must take a position on this. How is it possible to promote the realization that a nuclear war cannot be won, and must not be waged? Is there any basic conceptual idea of how to escape the fatal logic that the world finds itself trapped in? Within the continuing framework of nuclear deterrence, what possibilities are there for minimizing the inherent risks (technological solutions, fairly negotiated arms control)?

These are complex questions, and the aporias that become visible in them appear insoluble. There is no way around nuclear deterrence with the right and proper intention of maintaining peace in freedom. Nuclear deterrence understood in this way can also pave the way to disarmament. Those who are in positions of responsibility are objectively in a situation where it is difficult to act. In this context, repeating over and over that nuclear weapons are political weapons is probably only going to soothe the crises of conscience experienced by such persons.

Conclusion and outlook

Our examination of nuclear deterrence has shown it to be a tough nut to crack, both intellectually and ethically. Of course we could not expect to solve the aporias of nuclear deterrence. It has become clear that the major churches are increasingly withdrawing legitimacy from the concept of nuclear deterrence, as the pope did too during his recent visit to Japan. The so-called “interim ethics” is coming to an end – “still” is changing into “no longer”. On the other hand, we have to face the realities. Nuclear weapons and the knowledge of how to make them are in the world. Nuclear weapons cannot be “uninvented”. An increasing number of countries even see them as a “life insurance”. A unilateral renunciation of nuclear weapons in all likelihood would not lead to the goal. At the end of the day, it would amount to losing a bargaining chip for negotiations between equals. In this situation, it seems important to me to continue to step up arms control efforts. I would also like to see a debate in Germany that does justice to the seriousness of the issue and extends beyond specialist circles.

1 Rat der Evangelischen Kirche in Deutschland (2007): Aus Gottes Frieden leben – für gerechten Frieden sorgen. P. 103. (accessed March 3, 2020). (accessed March 3, 2020).

2 Overbeck, Franz-Josef (2019): Konstruktive Konfliktkultur. Friedensethische Standortbestimmung des Katholischen Militärbischofs für die Deutsche Bundeswehr. Freiburg im Breisgau, p. 106.

3 Permanent Mission of the Holy See to the United Nations and Other International Organizations in Geneva (2014): Nuclear Disarmament: Time for Abolition. P. 11. (accessed March 3, 2020). (accessed March 3, 2020).

4 Overbeck, Franz-Josef (2019), p. 101.

Generalleutnant a. D. Markus Bentler

Generalleutnant a. D. Markus Bentler, born in 1953, has been chairman of the Study Group of Catholic Officers (Studienkreises Katholischer Offiziere) since 2017. He was a member of the German Armed Forces (Bundeswehr) from 1972 to 2015. In the last of his multiple assignments, he served as German Military Representative in the Military Committee of NATO und the European Union.

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All articles in this issue

The End of the "Interlude" – Nuclear Deterrence in the Light of Roman Catholic Social Teaching
Heinz-Günther Stobbe
Waiting for Armageddon: Theological and Ethical Aspects Of Nuclear Deterrence
Drew Christiansen SJ
The Relevance of the Heidelberg Theses today
Ines-Jacqueline Werkner
Exposing Flaws in the Logic(s) of Nuclear Deterrence as an International Security Strategy – a Feminist Postcolonial Perspective
Madita Standke-Erdmann, Victoria Scheyer
We Are the Bomb: Opaque Financial Flows and Unwitting Involvement in Nuclear Armament
Robin Jaspert
Extended Nuclear Deterrence and Participation: Overcome Together, Don’t Go It Alone
Wolfgang Richter
Nuclear Arms Control, Disarmament and Nonproliferation Regimes in Deep Crisis
Tom Sauer
"No Way Out": Nuclear Weapons Remain An Important Factor in International Politics
Michael Rühle
Russian Nuclear Weapons: Reason or Feelings?
Konstantin Bogdanov
China’s Nuclear Strategy in a New Geopolitical Environment
Sven Bernhard Gareis


Markus Bentler
Burkhard Bleul