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The (In-)Effectiveness of "Deterrence" as an Instrument Against Jihadist Terrorist Threats

30 Mar 2015
Short Read by Bibi van Ginkel

When threat levels increase as a result of successful or foiled terrorist attacks, policymakers and politicians are faced with the question whether new or more severe measures are needed to contain the problem. Indeed, on many occasions, partly due to perceived public pressure, new plans are presented, rather than questions being asked whether that is really necessary, or whether it would make more sense to review the quality of the implementation of already existing policies. Thinking it is a strong message that would deter potential terrorists from committing new attacks, a minister might announce a new policy or a judge might pronounce a severe punishment. One apparently expects that the measure or sentence sends a warning to all those potentially thinking about joining the terrorist cause of a jihadist organisation. The question is however, does “deterrence” work as an instrument against terrorism?

In academic literature, most authors reject the idea of deterrence as an effective measure against terrorism. The concept especially played an important role during the Cold War, when a strategy of nuclear deterrence was followed to persuade the adversary that offensive nuclear action would come at the highest costs due to the devastating damage that would be inflicted in retaliation. This threat-based dissuasive method of conflict escalation prevention acts on the political will of an opponent, who is expected as a result of this method to make a rational cost-benefit analysis and decide against any offensive action, since it will not bring any long-term benefits. This narrow “classic” interpretation of deterrence as an instrument of dissuasion, however, does not appear to be able to deter potential jihadist terrorists effectively, as most actors do not consider the preservation of life on earth as a high priority. More modern interpretations of the concept of deterrence, on the other hand, show more nuances in interpretation and methods for implementation (see below). These modern interpretations merit a closer analysis to assess what kind of deterrence instruments could work effectively under what circumstances and targeted to what particular group.

Deterrence instruments could be aimed at preventing terrorist attacks from taking place, or could be aimed at lowering the risk or the impact of a potential attack. Especially in the latter case, these kinds of deterrence instruments could under certain circumstances work effectively. The risk of a terrorist attack taking place can be calculated as the sum of the probability that it occurs times the impact it might have. According to this formula, bringing the probability down and mitigating the potential impact of a terrorist attack might offer points of entry for shaping deterrence instruments.

Terrorists – whether working individually or as part of an organisation – aim for maximum result with an attack. This maxim result can be measured in physical damage (loss of lives, wounded people, destruction of buildings or infrastructure), economical damage, and the spreading of fear and social unrest in societies. Counter-terrorism policies, on the other hand, aim to prevent this from happening, or to mitigate these possible results. Terrorists also commit attacks to generate attention for a political cause, and legitimise the means used as ”just” in their struggle to reach that aim. It is important to realise that in drafting their strategy, they do not make the same kind of rational decisions in weighing the pros and the cons of an attack – including the risk they run of being killed in action – in the same manner as we do. Especially terrorists motivated by an extreme jihadist religious belief are convinced that dying for their cause will make them martyrs, and that paradise awaits them after their death, which is even better than life on earth. Under these circumstances it is hard to imagine measures that have a deterrent effect on these potential terrorists. On the contrary, certain measures, which are intended to have a deterrent effect, result in side effects that could undermine the intended purpose of the measure. This is, for instance, reportedly the case as a result of the attacks by armed drones in Pakistan and Yemen, which results in strengthening the solidarity in the support environment of the targeted individuals, uniting them in their shared hatred of the ”enemy” that attacks them, and, as a result, radicalising some of them to the point that they will become the next violent extremists.

Before assessing the various forms of deterrence, it is important to distinguish the different actors and their respective roles within a terrorist organisation, their tactics and modus operandi. The structures, especially  of large terrorist organisations, could include leaders who take strategic decisions and who are responsible for the (design of the) supporting infrastructure. They furthermore consist of mid-level operators, foot soldiers, and those working in the support network and (financial) facilitators. Each of them might feel differently about offering their own life for a higher cause, and might make a more or less rational decision before they take action. It is important to realise these distinctions, because the potential effectiveness of deterrence measures is very much related to that. Deterrence instruments could be targeted at the wider support network of the terrorist organisation, the facilitators, the infrastructure and the supply chains of weapons and explosives, or the leadership. What works effectively with regard to one group might not have the same deterrent effect on the other group.

As mentioned, there are various kinds of deterrence measures. Glenn Snyder distinguishes deterrence by denial and deterrence by punishment. In the latter case, the aim is to render the costs of committing an attack so high that they outweigh the benefits of the attack. This is for example Israel’s strategy of choice, where the measure of deterrence is often used as a form of retaliation against families and communities of terrorists – although not very effectively in the long run. The Israeli use this measure of deterrence often as a form of retaliation against the families and communities of terrorists. The reasoning behind the way these measures are implemented is based on the necessity to make them intentionally appear excessive and disproportional in order to convince hard-core terrorists to change their minds. A different example of deterrence by punishment is the threat of judicial criminal prosecution of Internet companies who spread jihadist content. Here the measure targets those companies that are providing the technical infrastructure for social media platforms that are abused by jihadist extremists to communicate their jihadist narratives with the intention to, for instance, recruit new foreign fighters. The threat of criminal prosecution of these companies, will most likely work effectively, and motivate these companies to take measures against the abuse of their media platforms.

In case of deterrence by denial, the idea is to discourage potential terrorist attackers by lowering their chances to succeed or by convincing them to pursue their political goals in a different manner. According to Paul Davis and Brian Jenkins, even the most committed and dangerous terrorists prefer to avoid running high operational risks. Thus, increasing the uncertainty regarding the likelihood of success for a planned operation, as well as increasing the risks of premature discovery might have a deterrent effect. Jeffrey Knopf’s proposed method of deterrence by counter-narrative and by legitimisation also falls within this broader category of deterrence by denial. This form of deterrence aims at undermining the narratives used by terrorist organisations as legitimisation for their use of violence.

James Smith and Brent Talbot distinguish three levels at which deterrence measures can be targeted: the tactical level, the operational level, and the strategic level. At the tactical level, deterrence by denial should especially be aimed at denial of opportunity to commit an attack, incite or recruit, for instance by increasing security and protection measures, and by augmenting the operational risk terrorists run during the preparatory phase of their attack. An example of such a measure could be the denial of a visa request of a radical imam who would otherwise likely incite individuals to become foreign fighters or to commit attacks in their home countries.

At the operational level denial of opportunity should be targeted at cutting off logistical support chains and financial support, which at the same time could be qualified as denial of capability. Drafting blacklists of individuals who are involved in terrorist activities and henceforth freezing their financial assets could therefore have an effect as a deterrent measure aimed at denial of capability. These kinds of measures can go hand in hand with deterrence by punishment measures, if criminal prosecution is used to go after those who violate the obligation not to financially support terrorists or supply them with explosive materials. In case these measures especially target the support group, Knopf qualifies these measures as indirect deterrence.

At the strategic level, deterrence through denial of objectives is according to Lee Dutter and Ofira Seliktar the most important level to apply deterrence measures. These measures could aim to convince supporters of the terrorist cause that there are other and more effective ways to attain their political goals. This could be given shape by spreading information about the negative experiences of former jihadist fighters who have returned. These measures could furthermore be aimed at preventing governments from overreacting in their responses to attacks, enhancing social resilience and managing fear. This category shows resemblance with the deterrence by counter-narrative measures mentioned above. An example of deterrence by public backlash, also falling in this same category, can be found on those occasions that as a result of excessive violence for instance against children, support of the wider group of sympathisers diminishes, and this group might even turn against the terrorists.

Obviously, some deterrence measures fall within more than one category. An example of a measure that aims at both denial of objectives as well as denial of capability, are those measures adopted to prevent ransom being paid for hostages taken by terrorists.

Unfortunately, many recently adopted measures have been presented to have a deterrent effect, whereas this is –at best – debatable, based on some of the research referred to above. This is, for instance, the case with the prosecution of those who attempt to travel to Syria and Iraq, or those acting as recruiters. The threat of prosecution or more severe punishment does not appear to work as deterrence. The same is true for measures to revoke citizenship, or for the prosecution of those who incite to commit acts of terrorism. Clearly, there might be other policy reasons to adopt these measures, such as the fact that it is the state’s prerogative to punish and apply sentences that reflect the sentiments of horror with the general public for the atrocities committed. However, policymakers and politicians should be aware of the fact that not all measures they adopt have a deterrent effect, and on occasion might even have an opposite effect. Only when all these potential effects are taken into account will it be possible to draft a comprehensive and effective counter-terrorism policy.


Benjamin Darnell, Deterrence in Counter Terrorism, 19 May 2010.

Matthew Kroenig and Barry Pavel, “How to Deter Terrorism”, in: The Washington Quarterly, Spring 2012, pp.21-36.

Jeffrey W. Knopf, "The Fourth Wave in Deterrence Research”, in: Contemporary Security Policy, Vol. 31, No.1 (April 2010), pp. 1-33.

Glenn Snyder, “Deterrence by Denial and Punishment”, in: Research Monograph No.1, Princeton University Center of International Studies, 1959.

Glenn Snyder, Deterrence and Defense: Toward a Theory of National Security, Princeton NJ, Princeton University Press, 1961.

Paul K. Davis and Brian Michael Jenkins, Deterrence and Influence in Counterterrorism: A Component in the War on al Qaeda, Santa Monica, CA: RAND, 2002.

James Smith and Brent Talbot, “Terrorism and Deterrence by Denial”, in: Paul R. Viotti, Michael A. Opheim and Nicholas Bowen (Eds), Terrorism and Homeland Security: Thinking Strategically about Policy. Boca Raton, FL, CRC Press, 2008.

Lee E. Dutter and Ofira Selktar, “To Martyr or Not to Martyr: Jihad is the Question, What Policy is the Answer?”, in: Studies in Conflict & Terrorism, Vol. 30, No. 5, May 2007, pp. 429-433.

Gerald M. Steinberg, “Rediscovering Deterrence after September 11, 2001”, in: Jerusalem Letter/Viewpoints, No 467, Jerusalem Center for Public Affairs, 2 December 2001.