Deterring Terrorists

“Only when not a single breach is visible in the iron wall, only then do extreme groups lose their sway, and influence transfers to moderate groups. Only then would these moderate groups come to us with proposals for mutual concessions. ”

— Ze’ev Jabotinsky, “The Iron Wall,” November 4, 1923

Israel has been waging a “War on Terror” since before it was established, with a high degree of success. However, during most of this period, the conventional wisdom there (as elsewhere) was that terrorists cannot be “deterred” and, therefore, that the strategy against them should focus on prevention, disruption, and offensive action in order to eradicate them. Numerous cases of failed deterrence seemed to verify this assumption: the Israeli withdrawal from South Lebanon in May 2000 and the outbreak of the second Intifada in October of that year, the attacks of September 11 and the continuing insurgency in Iraq, the ups and downs in the Indian struggle against the jihadi movement in Kashmir.

Nevertheless, looking closer at the history of Israel’s conflicts with terrorist organizations, we see that a de facto deterrence strategy was employed and often succeeded, achieving periods of relative quiet in both the Lebanese and the Palestinian theaters. In this article I will endeavor to draw an outline of the key elements that a strategy of deterrence against terrorists should take into account.

Relevant attributes of terrorist entities

The relationship between a defending state and a nonstate terrorist organization is inherently asymmetric. One successful attack out of tens or even hundreds of disrupted plans is a total success for the terrorist organization, whereas for the state it is a total failure. ¹ Terrorist organizations also enjoy the advantages of the weaker party. In the West Bank and Gaza, Lebanon, Iraq, and elsewhere, they take advantage of the Western commitment to international norms and conventions (constraints on indiscriminate firepower in the vicinity of civilians, the need to tailor operations to minimize civilian casualties, commitments regarding treatment of prisoners); create conditions for a humanitarian crisis that is left at the state ’s doorstep if it makes use of its superior power; and exploit the Western media to create an image of a terrorist potential which far exceeds what the terrorist organization is really capable of (promises of revenge for targeted killings or the widely publicized Iranian recruitment campaign of “martyrs” in case of an attack on Iran). Finally, they succeed in neutralizing the advantages of the state ’s superior power by decentralizing their command and control so that military successes of the state enemy in one sector are irrelevant in terms of deterrence for others.

The degree of state-like attributes of the organization and the extent of links between such an organization and a sovereign state, with all the burdens sovereignty entails, have a significant influence on strategies that can be implemented to deter that organization. The most salient of these attributes are ( 1) the role of culture and ideology — religious tenets, the existence of a “national” or transnational/religious agenda; (2) sources of authority, leadership and instruments of command and control; (3) the ways in which the leadership assesses the nature of the situation it faces as it attempts to fulfill its goals, including (at least) its self-assessment, its assessment of its allies ’ capability and will to assist, and its assessment of the identity, capabilities, and wills of its immediate and potential enemies (these are not objective, but are influenced by ingrained self-images and images of the “other”); (4) affinity with the “host population” or “host state,” actual control over territory and the existence of a social agenda and commitment towards that population; and ( 5) patron-proxy relationships and financial and logistic dependence and channels of supply. These attributes can explain many of the differences among the roads taken by disparate terrorist organizations — from national movements such as the ira to transnational religious ones such as al Qaeda.

Culture and ideology

Ultimately, deterrence is the result of mutual perceptions — self-image and the image of the enemy. These perceptions are laden with cultural and psychological overtones and passed through overlapping prisms of history, culture, language, and ideology. The relevance of these prisms and the need to tailor even strategic deterrence to the adversary has become more accepted in Western defense circles. ² This appears to be even more critical in cases of nonstate organizations.

All the organizations that have posed a formidable terrorist threat have been highly motivated ideologically, be it through a secular nationalist ideology (Fatah, the ira); a Sunni Islamic world view (Hamas, Islamic Jihad, the Mujahidin in Kashmir, and, of course, al Qaeda); or a Shiite jihad doctrine (Hezbollah, Mahdi Army). Nationalist ideology is arguably much more pragmatic than that which derives from religion. The goal of the nationalist ideology is, ultimately, to achieve independence for the nation. Consequently, even those national movements that employ terrorism take into account the political aspects of their actions. Such measures are judged by the pros and cons of their effect on the goal of a national state.

The underlying sources of the strategy of Islamic terrorist organizations, however, are divine dictates. Deterrent pressures attempt to signal, in fact, that actions which are sanctioned or even obliged by Islam are counterproductive to the group ’s collective interests. The ideological “antidote” to such deterrence is indeed potent; by entering the fray against all odds, the mujahidis proving his unconditional faith in Allah and will be rewarded accordingly. The declared strategic goals of these organizations — total destruction of the enemy by constant attrition — also restrict their tactical room for maneuver. Even if the leadership understands that the better part of valor is discretion, it has proven difficult in many cases to translate this understanding into religious dispensation for “capitulation” to deterrence or to market it to the rank and file. This difficulty is compounded in the case of a movement that subscribes to an apocalyptic world view, an expectation of the impending “end of days” —  an event horizon at which all pragmatic laws of balance of power and Realpolitik collapse.

Leadership: command and control

Ideology, however, is not static. It is usually based on living sources of authority that presume to interpret divine will. Therefore, the religious, ideological, and political authorities of these movements have been — and should be — the prime targets of deterrence. This calls first for accurately identifying these sources of authority and their roles. Then more tactical questions may be asked: internal interests of the leadership, its mechanism for threat assessment, its sensors for reading and passing on deterrent signals, and more. These elements are also heavily laden with cultural baggage.

The case of Hamas is illustrative. Its founder, Sheikh Ahmed Yassin, had, until his death in 2004, almost total operational authority but was not considered a spiritual authority. He and his successors received religious guidance from clerics in Egypt and Saudi Arabia. Similarly, many Asian Islamist movements, such as the milf in the Philippines and the Laskar Jihad in Indonesia, have requested fatwas from the Arab world to justify their actions. Pressure on these Middle Eastern religious authorities is a natural channel for deterrence. Authorities in many Muslim countries have brought such pressure to bear in order to bring about restrictions on domestic terrorism. During the heyday of the second Intifada, U.S. pressure on Saudi Arabia eventually produced a fatwa by Saudi Islamic authorities against suicide attacks. The aversion of Western democracies to intervention in religious affairs, though, has precluded any efforts to coerce these religious authorities in a manner that would serve Western deterrence goals.

The mechanism of a “source of emulation” (marja’ taqlid) in Shiite Islam holds much more potential for influencing the behavior of a Shiite organization. This has been evident in Hezbollah ’s response to criticism by senior Lebanese Shiite clerics after the last war. Those clerics see themselves as a moral compass for their communities and feel responsible for the maslaha (public interest) of their flock. Nevertheless, Shiite organizations that have accepted Khomeini ’s principle of velayat-e faqih (the rule of the jurisprudent) have limited leeway for implementation of this principle. For them, the identification of the public interest is the sole prerogative of the Iranian supreme leader.

Once the leadership has been convinced that a deterrent signal should be taken into account, it has dealt with all the other obstacles (ideological justification, spiritual leadership, patron states) and reached the conclusion that a robust line of command between the leadership and the terrorist forces is crucial for implementation and hence for successful deterrence. This is where Israeli efforts to deter Palestinian terrorism have often failed. The Palestinian leadership after Arafat had neither sticks nor carrots that it could use to impose its will on a host of warlords. Therefore, Israeli pressure on that leadership was in vain. In the case of Hamas too, the political leadership in the West Bank and Gaza have almost no influence on military activities financed and directed by the leadership in Damascus, which is less sensitive to Israeli pressures. On the other hand, Hezbollah, a centralized and disciplined organization, has shown restraint once a decision has been made to refrain from attacks. Particularly salient in this regard is the lack of response by Hezbollah to the February 2008 killing of Emad Moghniyya — a key figure in the organization’s leadership. The leadership was aware that cross-border attacks would allow Israel to retaliate more effectively than in the war of summer 2006, and therefore it tempered the natural urge for revenge. Not one shot was fired. The ira was another prime example of a leadership’s control over its terrorist elements.

Individualist or collective decision-making processes in the leaderships of the nonstate organizations have a crucial influence on the reception of deterrent signals. “Pluralist”³ decision-making (as opposed to a chaotic line of command and control) creates more chances for reception of deterrent signals than autocratic leadership paradigms. In the cases of Fatah under Arafat and Hezbollah under Nassrallah, it appears that only the leader ’s perception of Israeli threats was relevant. Even when other members of the leadership tended to accept deterrent signals, their positions were virtually immaterial. It is hard to know how the internal decision-making in al Qaeda works, but there are signs that there too it is bin Laden ’s perceptions of reality which prevail. Elements in the more pluralistic Hamas leadership, on the other hand, tend to have different interests that can be influenced.

Estimate of the situation

One primary method of deterrence is to take advantage of the image of the deterring entity held by the target. This image is sometimes “imported” from the intelligence apparatuses of the patron state (such as Syria or Iran) and sometimes built independently through an intelligence-collection process within the organization. Almost all terrorist groups demonstrate a strong interest in the media and the domestic debates of their enemies and even claim to base their assessments of their enemies ’ intentions and resolve to carry them out on such analyses.

Terrorist organizations that have intimate access to the open society of their enemies should find it relatively easy to draw correct conclusions regarding the political feasibility of their enemies ’ deterrent threats. The Israeli (and American) experience has shown the limitations of a democratic society. Adherence of a state to Western standards of rules of engagement contributes to the image of constraints that prevent it from bringing its military superiority into play. Past statements by Israeli leaders that “there is no military solution” to terrorism weakened the credibility of deterrent signals. The debate in the U.S. regarding Iraq clearly affects American deterrence credibility in the Middle East and toward potential terrorist threats elsewhere. Israel ’s rational restraint in the face of Iraqi missile attacks during the first Gulf War (1991) was interpreted by many Arabs in the context of a culture in which he who does not take revenge for wrongs perpetrated loses all status and invites further attacks. To counteract this image, the deterring party cannot suffice with occasional attempts to restore its deterrence (e.g., Israeli bombing of Lebanon and American bombing of Sudan and Afghanistan before 2001). In this and other contexts, memories tend to be short.

An important component of deterrence against terrorism is the perception by the terrorist organization that the deterring state enjoys “intelligence dominance.” Israel has enjoyed an image of an intelligence superpower with the ability to target terrorist leaders (and even state targets) at will. This image has been reinforced by successes in targeted killings of senior terrorist leaders, and even the narrow escape of other terrorist leaders when such attempts failed has not severely impaired it.

There is a certain relationship between deterrence and the images of states that are perceived as allied against terrorist organizations. Israel ’s deterrent image in the eyes of terrorist groups benefits from the perception of U.S. backing for Israeli counter-terrorism policies, which has been enhanced since September 11, 2001, and was reinforced during the last Lebanon War. There is no evidence that the American imbroglio in Iraq and the failure of the U.S. to capture bin Laden have diminished this perception. On the other side of the coin, the 2006 Lebanon War was perceived by many terrorist groups as a proxy war between the U.S. and Iran or even as a preview of a future American attack on Iran.

Relations with the host population

An important conclusion one may reach is that terrorist groups based on nationalism or “Islamist nationalism” (i.e., primarily national movements which have latched onto the Islamic standard) are far more sensitive to their “host populations” than pure Islamist movements. A nationalist movement is usually rooted in the interests of its constituency host population, as it has no alternative to that population. This is true of Fatah — particularly after the traditional dichotomy of the predominant external leadership and the internal constituency was resolved with the internalization of the former after the Oslo Accords. In the case of Hamas, the February 2006 elections strengthened the need to cater to the constituency that had brought it to power; however, the continued supremacy of the external leadership prevents the internal interest from becoming predominant. Surely the host population was a prime interest of such movements as the ira, the pkk in Turkey, and even the indigenous Chechnyan leadership of the Chechnyan rebellion (as opposed to the imported Wahhabis).

Many Islamist movements, on the other hand, are not bound to this calculus. In some cases this is due to their identification with a transnational community that has wider interests that supersede pragmatic local political ones. True, bin Laden may have taken into account a devastating retaliation against his safe haven in Afghanistan, but Afghanistan is only a small — and from the point of view of Islam insignificant — corner of the Muslim ummah. Afghanistan and the Afghans were, in the eyes of bin Laden and his Arab followers, the match of the fire of the Islamist revival. Hezbollah, too, has a limited affinity with the host state, Lebanon. Though it has been involved in parliamentary life and even took part in government after the Syrian withdrawal, its attempts to prove its Lebanese character and deny that it is, in essence, an Iranian proxy have been unsuccessful. The acceptance of the principle of velayat-e faqih by the leadership of Hezbollah limits its ability to pressure its host population.

Proxy-patron relationships

Proxy-patron relationships have been overgeneralized in policy discussions of terrorist organizations and their ties to state supporters. A correct understanding of the nature of the specific relationship between each group and its patron state is critical for any attempt to deter a terrorist organization or to degrade its capabilities through the patron. One may roughly draw at least four types of relationships on a descending scale of the dependence of the terrorist organization on the patron:

Surrogates. These are terrorist organizations which are not separate from the state that supports them and are, in fact, creations of those states and directly and totally controlled by them. Such were the terrorist branches of the Syrian and Iraqi Ba ’ath, various bogus movements created by the Iranian regime against neighboring regimes ( “The Islamic Front for the Liberation of Bahrain/Qatar/etc.,” Turkish Hezbollah, et al.). To a certain extent, it would be correct to include Lebanese Hezbollah in this category. It is totally bound religiously, ideologically, financially, and militarily to the Iranian regime. Without that support it would wither and die.

Proxies. These are organizations that have been indentured by states for their own purposes. These organizations serve as proxies of those states while they are under their patronage but can move from one patron to another as their own interests dictate. Such are the cases of the Abu Nidal Organization, which acted successively for Iraq, Syria, Libya, and Iran; and various Palestinian organizations under Syrian patronage. The characteristic of this type of relationship is usually the physical presence of the main body of the proxy and most of its interests in the borders of the patron state.

Partnerships. This model relates to terrorist organizations that have assets of their own but form a relationship with a state. This may be based on a real community of ideological perception, or it may be a marriage of convenience. In any case, these affiliations are the weakest of the three types. Cases in point are the relationship between Lebanese Hezbollah and Syria when Syria was (openly) present in Lebanon; al Qaeda ’s relationship with Sudan and later with the Taliban; Iran’s relationship with Hamas and other Sunni organizations which would prefer not to be seen as proxies of Shiite Iran; the ira’s relationship with Libya in the early 1970s; and the Afghani mujahidin relationship with the U.S. and the uk during the war in Afghanistan.  

Reverse proxyship. Along with the terrorist organizations becoming proxies of Arab or other states, a reverse process can also be identified in which the proverbial tail wags the dog. The freedom of action that Afghanistan under the Taliban accorded al Qaeda reflected both the failure of the Taliban to internalize its statehood and a total identification of the Taliban with the al Qaeda narrative to the point that it was willing to risk the consequences of this identification. There are signs that Syria under Bashar al-Asad is undergoing a similar process in relation to Hezbollah; Bashar ’s public statements have grown closer and closer in substance to those of Hassan Nasrallah and seem to reflect an adoption of the Hezbollah-Iran narrative. This should raise the question of whether Syria will necessarily react to deterrence as Syria per se or might behave with less caution out of its identification with Hezbollah.

Modes of deterrence

On the basis of the above analysis one may outline a strategy for deterring terrorist organizations based on four main pillars: ( 1) direct military deterrence towards the terrorist leadership; (2) threatening the institutionalized assets of the “host” country; (3) pressuring the host population; (4) covert “human influence”operations (psyops); and (5) pressuring the terrorist organization’s patron entities.

Direct deterrence. The first pillar — direct military intervention and disruption — has been the core of Israel’s de facto deterrence of Hezbollah and Palestinian organizations. Israeli disruptive actions against the Palestinian organizations — particularly targeted killings of top-level activists — have had a temporary deterrent effect. The most salient example has been the series of targeted killings that Israel implemented in 2003. During that period, every activist at any level had to take into account that his movements might result in his death. This eventually brought the leadership to a de facto moratorium on suicide attacks. This period also gave birth to the discussion of a cease-fire. Paradoxically, while the assassination of key leaders has raised the price for surviving leaders, it has frequently disrupted their chains of command and complicated the implementation of decisions.

The more a terrorist organization achieves success in taking on the attributes and interests of a state, the more susceptible it becomes to deterrence. This is because the attributes of a state are real assets that can be damaged and are important enough for the terrorist leadership to constrain its policies in order to preserve them. These assets also constrain the leadership directly; its attention becomes directed towards nurturing and preserving them, and it becomes accustomed to enjoying their benefits. One of the more significant cases of this type of development was the plo presence in Lebanon before 1982. The question of whether Hezbollah has undergone a process of “Lebanonization” remains on the table and is debated among experts.

Such deterrence is almost always tactical and not strategic. The paradigm of strategic deterrence, in which one state can cause damage to another on the strategic level, is almost never applicable towards terrorist organizations. Nevertheless, tactical threats towards terrorist organizations can result in temporary deterrence. The conclusions that arise from this analysis are:

1. Tactical deterrence towards terrorist organizations usually derives from actions that have been taken recently (as opposed to declarations and signaling, which are the main building blocks of strategic deterrence); the terrorist organization knows that an attack of one type or another has, in the recent past, resulted in a certain retaliation and it has to take that into account.

2. Declarations that are not fulfilled create “negative deterrence.” Such a case is rare in a paradigm of strategic deterrence between states (and certainly in nuclear deterrence). In attempts to deter terrorism, though, negative deterrence is a daily phenomenon.

3. Tactical deterrence begins to erode the moment it is fielded. If it is not replenished from time to time by actions, it loses its efficacy. This, of course, differs from paradigms of strategic deterrence, which are based on a much more stable perception of the other side ’s capabilities and the conditions under which it may act.

4. Tactical deterrence is frequently nearly indistinguishable from operational considerations. The goal of the terrorist leader is to carry out the attack or attacks. If he receives signs of high alert from the defending side that may thwart his efforts, he may freeze the operation until such time as the alert goes down. This, it is claimed, is not an expression of deterrence but a purely tactical consideration.

5. Tactical deterrence is based on execution of a threat, as opposed to the core definition of deterrence which is, as noted above, the threat of punishment. It has been claimed that, as in other areas, “familiarity breeds contempt”; a threat of punishment of unknown proportions looms much darker than a punishment which is meted out on a regular basis.

Deterrence via host states. The affinity with and dependence of the nonstate actor on its relationship with existing states have been important channels for deterring terrorist actors. This has been demonstrated in the case of Fatah, when pressure on the material interests of the Palestinian Authority has brought about occasional restraint of Fatah elements in the field. This has also been true in the aftermath of the second Lebanon War, when the dependence of Hezbollah on a modus vivendi with the Lebanese state allowed the state to impose restraints on the guerilla group, at least for a time.

The efficacy of this strategy depends largely on the community of interests between the host and the organization that is the ultimate target of deterrence. The greater the identification between the two, or the closer a nonstate actor gets to being a state, the more susceptible it is to deterrence. Fatah, for example, evolved into a state-like entity, gathered interests and assets, and hence has become vulnerable to deterrence methods. Effective and credible threats to the hosts have the potential of deterring terrorist organizations from actions that would harm the host in a manner that would also inflict serious damage on the organizations themselves. Israel has not, however, succeeded in generating such deterrence. Both hosts (the pa and Lebanon) have benefited from Israeli weakness; Israel (and the West) has had a political interest in the continuing functioning of the pa and Lebanon so as not to have even greater chaos at its doorstep or, in the case of the pa, in order not to have to take over its civil functions and re-occupy the West Bank and Gaza. This has restrained any Israeli response that could conceivably bring about a collapse of those entities.

Another channel for indirect deterrence of patron states has been the international community. The risk of international sanctions has always been considered a potential deterrent. Such sanctions have been implemented against the pa, Afghanistan under the Taliban, Syria, and Iran. However, without the total commitment of the international community, it is doubtful that such measures will ever have any real effect.

A terrorist organization can, theoretically, completely take over its host state, internalizing state-like considerations and constraints and a state-like viewpoint of the cost-benefit ratio of continuing to be involved in terrorism. This was the Israeli expectation when it signed the Oslo Accords and granted the plo authority over the West Bank and Gaza, and it could conceivably be tested in the case of Lebanon if Hezbollah is able to gain complete power. This would suggest that the best way to install stable deterrence vis- à-vis terrorist organizations is to allow them to take over states. However, this paradigm has not proven itself; the pa has “preferred” to remain a failed state, unable or unwilling to control its terrorist components, and Hezbollah has, until recently, restrained itself from attempting to take over Lebanon. Furthermore, in most cases of Arab and Islamic organizations, any trend towards institutionalization of a terrorist entity induces a split in those organizations, with the splinter groups rejecting any moderation of positions.

Deterrence via the populace. Indirect deterrence through the host populace was openly attempted in Israel’s confrontations with Palestinian terrorist organizations and with Hezbollah in Lebanon. This has met with only modest success. The ability of a democratic state to take full advantage of this element is curtailed by its perception of its international commitments to the laws of war and human rights, not to mention its status as an occupying power (when such a case applies). Pamphlets distributed over Gaza and South Lebanon (when Israeli forces were physically present in those places) could not warn the populace of levels of retribution that Israel, as a state committed to the Geneva conventions, could not implement. While Israel is no longer the occupying power of those two areas, the legal debate in Israel severely constrains the government and the military from actions (particularly against Gaza) which would be considered legitimate acts of war against an enemy state.

⁴ The recent steps by Hezbollah in Lebanon are construed in Israel as having a bright side to them (similar assessments were heard after the Hamas takeover of Gaza); if Lebanon were officially ruled by Hezbollah, Israel would be less constrained in actions against it as an “enemy state.” However, Hezbollah is aware of this thinking and until now has preferred to hold indirect power in Lebanon, enhancing its status as a state-within-a-state.

Proposals for indirect deterrence of Palestinian organizations have been raised. One such was to present a “price table” for launching Qassam missiles from Gaza by linking the Israeli early warning system for short-range rockets ⁵ to the Gaza electric grid in Israel so that every launching of a rocket would turn off the electricity in Gaza for one hour. The “automatic” blackouts would, according to this proposal, bring about public pressure on Hamas to refrain from launching rockets at certain hours. This proposal was never seriously discussed.

Human influence operations. The role of propaganda and psyops is pivotal for deterrence through a host population and for reducing the ability of the natural constituency of the terrorists to recruit to the organization. However, overt propaganda can be counterproductive: There is a basis for the argument that Israeli and American efforts to woo the terrorist constituency by Arabic-language broadcasts projecting an image of openness and free press (lacking in the Arab countries) has had such an effect and that the goal of deterrence would have been better served by amplifying the threat of vast retribution in case of attack. ⁶

The internet has become a major battlefield in the war against terror. In the past, terrorist organizations would disseminate their ideology and communiqu és in pamphlets in the streets and the mosques. During the first Intifada, these pamphlets became the main conduit for guiding the populace in its support of the militants. Israeli efforts then focused not on refuting the arguments in the pamphlets but on saturating the field with such large amounts of contradictory material that the populace could not determine what was genuine and what was not and lost interest in all of them. Such methods were also utilized by terrorist organizations themselves against their own adversaries and by the kgb against Soviet dissident organizations. Such actions, however, call for the capability to mass-produce psyops products (with deep cultural, linguistic, and religious understanding of the terrain) and not to allow bureaucratic and legal considerations to reduce them to occasional pinpoint operations or to politically correct but unconvincing tracts.

Deterrence via the patron state. The final pillar is indirect deterrence via the patron state. In the Middle Eastern experience, the patron is frequently not the host state, though the Kurdish pkk did have bases in Iran and Syria which were used against Turkey, the anti-Iranian Mujahidin Khalk Organization ( mko) had bases in Saddam Hussein’s Iraq, and the anti-Iraqi sciri and Da’wah organizations had bases in Iran. This was the basis of Israel’s strategy of deterrence against terrorism in the early days of the state. Reprisals were launched against the states (Egypt, Jordan, and Lebanon) in a manner that was intended to bring them to rein in the terrorists. The efficacy of this method is directly related to the nature of the proxy-patron relationship as described above.

This pillar is closely linked to the proxy-patron relationship. The stronger that is, the less influential the host state may be, and in the cases in which the nonstate terrorist organization adopts the strategic interests and narrative of its patron, the host ’s interests become secondary. Conversely, the stronger the relationship is, the more effective indirect deterrence through the patron can be. Ultimately, when levers for deterrence of the patron state exist, the transfer of deterrence from the patron state to the nonstate proxy is not a complicated decision-making process. This is certainly true today in the relationship between Hezbollah and Iran.

However, in practice, options for deterring patron states have been restricted by strategic considerations related to those states which are extraneous to the issue of their support of terrorism; regional issues (Iran-Iraq, Lebanon, Pakistan-Afghanistan); proliferation issues (Iran, Pakistan); the absence of a common border (Israel vis- à-vis Iran); fear of terrorist retaliation by the patron state; or the very existence of such a border, which makes deterrent signaling a delicate step and risks deterioration into undesired hostilities. Hence, Israeli deterrence towards Syria has been impaired by the fact that Syria and its proxies know that Israel has had no interest in risking a full-fledged war with Syria over acts of terror.

Deterrable

The asymmetry between states and terrorist organizations seems to render paradigms tailored to strategic nuclear deterrence inappropriate. These theories tend to focus on the relationships between states and on the unspeakable damage that can be inflicted at the high end of potential conflict, either between conventional armies or in a nuclear conflict. These theories neglect pre-modern doctrines of deterrence which states have employed since time immemorial vis- à-vis both states and nonstate actors (insurgents, guerillas, terrorists).

One conclusion from the above discussion is the need to make a distinction between strategic and tactical deterrence. Israel and the United States have succeeded in maintaining strategic deterrence vis- à-vis actual and potential adversaries through high-end conventional capabilities on the ground and in the air and through a declared or assumed nonconventional capability. Deterrence of terrorist organizations, however, has been based — when it existed — mainly on tactical deterrence through day-to-day actions, which add up to an ever-shifting perception of the object of deterrence.

While it is true that the individual suicide bomber cannot be deterred, the main conclusion of this article is that deterrence towards terrorist organizations is possible. Israel has achieved temporary and fragile deterrence vis- à-vis Hezbollah and the Palestinians over the years. There is no doubt that some periods of relative quiet have derived from a desire not to provoke an Israeli reaction to a terrorist attack that would neutralize any benefit from such an attack. This occasional tactical deterrence has been achieved not by the threat of force or by an image of Israel ’s capability (after all, the terrorist organization is, by definition, struggling against a much stronger adversary), but by actual application of force and by inducing the fear that the force would be reapplied and even increased.

Deterrence of this type is difficult to distinguish from disruption or from operational considerations that dictate when and where to perform acts of terrorism — as opposed to deterrence that deals with whether or not to do it. Deterrence in such cases does not take effect immediately after force has been applied, but after a period of situation estimate, and after some time its effects begin to wear off. One may say that effective deterrence has an element of dramaturgy; a gun that fires in the first act is no longer relevant for dramatic purposes in the last act. The “audience” gets used to the shots and the deterrence is eroded. Hence, it is necessary from time to time to refresh the awareness of the terrorist leadership that the state will indeed employ force. To paraphrase a well-known expression of classic deterrence, the state that attempts to deter terrorism must “ speak loudly and periodically use a big stick.