Conclusion: Insights from Theory and Practice

Strategists are fond of saying that the nature of war is immutable, but its character is not. Even Von Clausewitz, whose very objective was to develop a general theory of war, held that every age has “its own kind of war, its own limiting conditions, and its own peculiar preconceptions.” The same can be said for strategy. History offers ample examples of strategic concepts that guide how means are to be connected to political ends in order to defeat adversaries in particular historical contexts. Warfighting concepts have included dislocation and exhaustion to target the adversary’s will, and attrition and annihilation to deal with its capabilities.

The Essence of Cross-Domain Deterrence

Both deterrence theory and deterrence practice are evolving to address contemporary strategic challenges. In the military domain, states progressively integrate and synchronise military operations. Outside of it, they exploit grey zone strategies that combine different instruments of influence across multiple domains. These developments are now giving birth to a new wave of thinking about cross domain deterrence (CDD), what it precisely entails, and what favouring conditions are necessary for it to be effective. This chapter situates CDD in the context of today’s challenges, and identifies the prerequisites for these favouring conditions based on a review of a rather diverse body of literature. It finds that one strand of that literature predominantly focuses on practical and technical prerequisites in order for CDD to be effective, leaving the framework of traditional deterrence theory intact. It also finds a second strand that holds that the nature of today’s challenges requires more than mere innovation in application. The ideas about deterrence proposed by this second strand are expanding on common understandings of deterrence to the extent that deterrence is no longer only about fear nor about convincing opponents to refrain from certain behaviour. The conclusion summarises the findings and elaborates their implications for theory and practice.

Nuclear Deterrence: A Guarantee for or Threat to Strategic Stability?

In recent literature, much attention has been paid to factors that affect nuclear deterrence and stability from the outside: new missile defence systems, non-nuclear (conventional) high-precision long-range weapons, the influence of third and threshold nuclear states, space weapons, and—more recently—cyber threats. These new factors have pushed the core of nuclear deterrence—strategic relations between Russia and the United States—to the background in the public consciousness. Yet dangerous changes are taking place. This chapter examines the real and imaginary causes of the current situation and suggests potential ways to reduce tensions that could benefit international security. It concludes that nuclear deterrence can serve as a pillar of international security with one crucial reservation: namely, that it can only work in conjunction with negotiations and agreements on the limitation, reduction, and non-proliferation of nuclear weapons. Without such checks, nuclear deterrence goes berserk. It endlessly fuels the arms race, brings the great powers to the brink of nuclear war in any serious crisis, and sometimes the very dynamics of nuclear deterrence can instigate a confrontation.

Deterrence: A Continuation of Emotional Life with the Admixture of Violent Means

Deterrence is more than anything a psychological mechanism. It depends on emotions that orchestrate processes across organisms to deal with the challenges of the present and the future. However, deterrence scholarship has had a turbulent relationship with emotions. The main aim of this chapter is to review what we know and what we do not know about emotions and deterrence. The secondary aim is to develop a dynamic and interactive emotion-centric model of deterrence to explain where and how emotions play a role in such a mechanism. We combine the methods of theoretical analysis and literature review to achieve these aims. Our findings indicate that emotions give a new meaning to deterrence by changing the nature of the theory and by highlighting problems of practice. More specifically, scholars should reconsider both the means and the ends of deterrence. Practitioners should be aware that deterrence efforts are hard to sustain and may produce emotional effects detrimental to their original purpose.

New Technologies and Deterrence: Artificial Intelligence and Adversarial Behaviour

Offering a critical synthesis of extant insights into technological developments in AI and their potential ramifications for international relations and deterrence postures, this chapter argues that AI risks influencing military deterrence and coercion in unique ways: it may alter cost-benefit calculations by removing the fog of war, by superficially imposing rationality on political decisions, and by diminishing the human cost of military engagement. It may recalibrate the balance between offensive and defensive measures, tipping the scales in favour of pre-emption, and undermine existing assumptions imbedded in both conventional and nuclear deterrence. AI might altogether remove human emotions and eliminate other biological limitations from the practice of coercion. It may provide users the ability to collect, synthesize, and act upon real-time intelligence from several disparate sources, augmenting the certainty and severity of punishment strategies, both in theatre and online, compressing the distance between intelligence, political decisions, and coercive action. As a result, AI may quicken the overall pace of action across all domains of coercion, in conflict, crisis, and war, and within the related subfields of national security, counterterrorism, counter-crime, and counter-espionage.

Deterrence by Punishment or Denial? The eFP Case

In 2017 NATO initiated Enhanced Forward Presence (eFP) in the Baltics to deter Russia. While most studies analyse eFP from the perspective of NATO or the troop contributing countries, this chapter addresses the question how the host nations, i.e. in this contribution Estonia, Latvia and Lithuania, perceive the deterrence strategy underlying eFP as well as their own strategies. In doing this, the chapter emphasizes how strategic culture influences the Baltic countries’ behaviour towards deterrence. We found that in Estonia perspectives on eFP were ambiguous. While official documents reflect the official NATO narrative based on deterrence by punishment other sources stress the illusion, expectation or aspiration of deterrence by denial. In Lithuania, documents, officials and experts emphasize deterrence by denial as opposed to deterrence by punishment. Latvia considers the strategy behind eFP as deterrence by punishment. The strategic cultures, the history and threat perceptions of the Baltic states explain these differences to a large extent. In particular the presence of Russophone minorities in Estonia and Latvia, lead to some reluctance in fully embracing NATO’s strategy, while at the same time both countries prepare to counter Russia’s threat with their allies.

What’s on the Human Mind? Decision Theory and Deterrence

Indeed, deterrence, as Freedman and Mazarr recount in this volume in respectively Chaps. 10.1007/978-94-6265-419-8_1 and 10.1007/978-94-6265-419-8_2, aims to dissuade an opponent from taking undesirable actions. Clear communication of demands (a red line for instance), coupled with a credible threat to inflict pain if necessary, and demonstration of resolve are some obvious essential elements for creating effective deterrence. Success crucially also depends on whether the opponent receives the intended signal, interprets it as intended, and has the perception that the message is congruent with reality, i.e., that the opponent can make good on her threats. Success furthermore assumes that the demands communicated are acceptable. If those prerequisites exist, theory suggests a rational actor will back down, after weighing the benefits of the envisioned actions versus the potential costs that may result when the threat is executed. This chapter offers a synthesis of insights that have appeared since the 1980s that fundamentally challenge that assumption of rationality. This contribution about the workings of the human mind concerns the various filters and cognitive shortcuts that colour the incoming stream of information and the processes to digest it and come to a decision.

Introduction—The Evolution of Deterrence Strategy and Research

The concept of deterrence has dominated Western strategic thought for some seven decades. It shows no signs of easing its grip. In the face of any new security threat, such as terrorism or cyber-attacks, one of the first questions to be asked is ‘can this be deterred?’ Even when the answer is not very encouraging the inclination is to persevere until some way is found at least to reduce if not remove the threat through some form of deterrence. This may have less to do with deterrence’s reliability or effectiveness as a strategy and more because of its inherent normative appeal. When a state adopts a deterrence strategy it signals that it does not seek a fight but still considers some interests to be so vital that they are worth fighting for. It implies a defensive intent without weakness. It seeks to prevent aggression while being non-aggressive. It sustains rather than disrupts the status quo. For these reasons, it has positive associations that other potential strategies lack. Appeasement as a deliberate strategy has been discredited since the 1930s; conquering other states is now seen to be as demanding as it is illegal. There is no dishonour in deterrence.

Nuclear Deterrence in the Algorithmic Age: Game Theory Revisited

Commonly used game and decision theoretic models fail to explain the empirics of deterrence. This has unjustly led many theorists to criticize the (rationality and other) assumptions underpinning of such models. No serious game theorist will contend that his theoretic model will possibly take account of all the peculiarities involved in decision making and therefore be an accurate model of such situations. Games are an aid to thinking about some of the aspects of the broader situation. Game theory models prescribe what a decision maker ought to do in a given situation, not what a decision maker actually does. To maintain nuclear strategic stability, it is of paramount importance to understand the dynamical interplay between all players involved in decision making processes with regard to nuclear strategy. History has shown some progress in understanding nuclear deterrence by the use of initial game- and decision theoretic models to alleviate the burden of human cognitive biases. Since it is highly likely that (semi-)autonomous systems will in some way participate in the future nuclear strategic landscape, combined with the fact that the nuclear deterrent decision-cycle will also be based on algorithmic analysis, rational deterrence theory is and should be an integral element of strategic thinking about nuclear deterrence. That, or it might as well be game over.

Deterrence (In)stability Between India and Pakistan

Since the introduction of India’s cold start and Pakistan’s full spectrum deterrence doctrines, the subcontinental deterrence landscape has been characterised by strong cross-domain dynamics. In extremis, if both states adhere to the threats issued in their doctrines a Pakistan-supported militant attack on Indian soil could escalate into an all-out nuclear exchange. It is a development that has been met with great concern by many analysts for its detrimental impact on deterrence stability. Since the doctrines are believed to have become operational, at least four incidents occurred which could have sparked this cross-domain escalation spiral. And yet, crisis behaviour proved vastly different from what doctrine predicted. What does this say about deterrence stability on the subcontinent? This chapter assesses deterrence stability on the basis of perfect deterrence theory, which is argued to provide a more nuanced view of deterrence relationships than classical deterrence theory. It finds support for the stability-instability paradox and argues that deterrence is less unstable than appears at first sight. Furthermore, to fully appreciate the degree of deterrence stability, it is suggested that the factors ‘context’ and ‘narrative’ should be included into the equation.