Deterrence — Sounds simple, not so straightforward in practice

27 Oct 2022

Air Marshal (ret’d) John Harvey AM PhD, unpacks deterrence theory amid major developments in the strategic environment.

Over the last 12 months or so there has been considerable talk about deterrence, particularly in relation to how China might be deterred from taking military action against Taiwan. There is a general understanding of the nature of deterrence, i.e. the threatened use of force to convince an adversary ‘not to do something’. In practice, however, effective deterrence is complex, especially when the threat is based on conventional weapons and when the actor or actors posing the threat are not necessarily committed to carrying out that threat if deterrence fails.

Based on the desire to better understand the nature of conventional deterrence, some 25 years ago I conducted a detailed study of conventional deterrence, comprising:

  • the relevance of conventional deterrence;
  • forms of deterrence; deterrence theory;
  • empirical analysis – the historical record; and
  • criticisms and limitations of conventional deterrence.

The full study is available here. From this detailed study a number of conclusions were drawn.

In the 25 years since the study was completed three major developments in the strategic environment that potentially change the nature and application of conventional deterrence can be identified:

  1. The importance of the information domain in warfare and the development of cyberwarfare;
  2. The increased importance of space to military operations; and
  3. The rise of China as a major military power across all warfare domains, with nuclear weapons and advanced delivery systems and a challenger to the rules-based order established since the end of World War II led by the United States.

On re-reading the study, notwithstanding these major developments, the conclusions drawn from the original study remain valid and need to be taken into account in any assessment of the likely success of a deterrence strategy.  The conclusions, unchanged from the original study follow.


The [preceding] analysis shows that deterrence, while generally well-understood as a concept and widely applied in military and non-military contexts, is complex when considered in detail. The complexity is due to the interactive nature of any deterrence situation which involves a wide range of strategic, political, and psychological factors.

This is particularly so for conventional deterrence and has led to a wide range of criticisms regarding its conceptual basis, theoretical understanding, and effectiveness in practice.

While not negating the value of conventional deterrence, these criticisms highlight its inherentcontestability. This contestability is supported by the results of empirical analyses which, while providing conflicting results on the success of conventional deterrence, show that it can be effective in practice. Because it can be effective and because peace-loving nations will always prefer to deter conflict than to fight, conventional deterrence will remain a fundamental feature of security strategies.

But because conventional deterrence can fail its weaknesses as well as its strengths must be recognised.

Specific conclusions which can be drawn from the preceding analysis are as follows: