The challenge of deterrence — discouraging states from taking unwanted actions, especially military aggression — has again become a principal theme in U.S. defence policy. This chapter reviews the fundamentals of deterrence in theory and practice. It surveys basic de fi nitions and types of deterrence, …

This chapter examines the theoretical principles that underpin conventional deterrence and its evolution in practice over the past century. It disaggregates conventional deterrence approaches into four strategic categories based on their geographic scope and the nature of the threats they employ, and …

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 in fl uence of third and threshold nuclear states, space weapons, and — more recently …

The U.S. provides extended nuclear deterrence to allies in Europe, Asia, and elsewhere. The 2018 NPR signals several potentially destabilizing policies, including lowering the threshold for use and adding low-yield capabilities, and it emphasizes the need for nuclear superiority. This chapter argues …

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 …

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 in fl uence across …

This chapter traces the evolution of Russian thinking on deterrence and makes three arguments. First, the Russian approach to deterrence differs from the Western conceptualization of this term. Deterrence a la Ruse is much broader than the meaning that Western experts have in mind. It stands for the …

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 …

Iran has been a critical player in the Syrian war since 2011, crafting a complex foreign policy and military strategy to preserve its Syrian ally. What have been the drivers of Iranian decision-making in this con fl ict? And how has Iranian strategy evolved over the course of the war? This chapter argues …

The chapter examines the relevance and applicability of deterrence to violent non-state actors (VNSAs). VNSAs have become important players in the international system. Traditional deterrence theory and practice has limited utility against VNSAs due to their different characteristics to those of states …