The analytic literature on the causes and prevention of terrorism, and militant campaigns of strategic violence more generally, has exploded in the last decade. Alex Schmid's Routledge Handbook of Terrorism Research contains a comprehensive bibliography of about 4,000 items, most published since 2000, organized under 21 substantive headings that range from etiologies to ideologies to countermeasures. Yet, as Schmid points out, there is no consensus on definitions or boundaries. His critical review of definitional issues (pp. 39–98) is accompanied by an appendix listing some 250 academic and official definitions, from Robspierre (1794) to Louise Richardson (2006). Schmid makes two important contributions here. One is a social scientific definition that is as close to consensus as we shall ever get; the other is a set of distinctions among the characteristics of different types of political action, violent and nonviolent. This helps provide an antidote to overly general usages of the term terrorism in public and some academic discourse.

A related contribution of the Handbook is a review and critique of typologies by Schmid and Sarah Marsden (pp. 158–200). They provide conceptual mappings of types of violent political action, motivations, organizations, and operations. Also surveyed are 20 publically accessible databases on incidents of terrorism, and political violence more generally, that are available for new empirical research. And there is a world directory of terrorist and extremist groups organized by region and countries in which they are active. This handbook is far richer than a similar review compiled in 1988 by Schmid and A. J. Jongman, Political Terrorism: A New Guide to Actors, Authors, Concepts, Data Bases.

Much of the newer literature on terrorism is hortatory, filled with alarms and calls for action. One might cite titles like Imperial Hubris: Why the West is Losing the War on Terror (Michael Scheuer, 2004) and Terror Incorporated (Loretta Napoleoni, 2005; a book about the financing of terrorist organizations that is better than its hyperbolic title implies). Yet embedded in these writings are serious theoretical arguments and evidence about etiology across all levels of analysis, from the individual to the international. There is, first of all—in the Handbook's dense 79-page review of “Theories of Terrorism” (by Bradley McAllister and Alex Schmid)—terrorism carried out or sponsored by states. This subject has its own rich theoretical literature, largely divorced from the analysis of oppositional terrorism. The latter theories, and relevant bodies of case studies and empirical evidence, tell us a great deal about how individuals are recruited and socialized into terrorist movements, the structure and leadership of militant organizations, and the social and political settings that give rise to them. The ideologies that support terrorism, like Salafism and jihadism, and anarchism in a past era, are a rich subject of inquiry and arguably provide more insight into the psychosocial dynamics of terror movements than analyses that focus on the “structural” or “root” causes of terrorism. There is also an emerging literature on dyadic theories, that is, those that examine interactions between counterterrorists and their antagonists.

McAllister and Schmid deplore the lack of common ground among theories and research on the subject—if indeed there is a coherent subject: “Despite much theorizing, there is no general theory of terrorism. If it existed, it would have to be a sub-theory of general theories of violence and conflict. Most theorizing not only fails to make that link, but is even negligent of the obvious link between non-state terrorism and governmental counter-actions” (p. 261). Nonetheless, the cumulation of knowledge is substantial and, along with the proliferation of global data sets, should provide a great deal of impetus for better research and theory.

Cutting the Fuse, another somewhat hyperbolic title, is a careful comparative study by the Chicago Project on Security and Terrorism. It is a follow-on to Robert Pape's Dying to Win: The Strategic Logic of Suicide Terrorism (2005) and his equally influential 2003 article in the American Political Science Review, “The Strategic Logic of Suicide Terrorism.” He points out, for example, that six of 11 suicide terrorism campaigns since 1980 ended in partial achievement of the terrorist movements' objectives. This is so because suicide campaigns have enormous leverage on democratic regimes that are adverse to loss of life. In Cutting the Fuse, the authors recount the finding that suicide attacks between 1980 and 2001 accounted for only 3% of all terrorist attacks worldwide but accounted for 70% of terrorist deaths.

In their new study, Pape and James Feldman analyze systematically and in depth the seven most deadly campaigns of suicide terrorism from the 1980s through 2009, identifying their causes, the ebb and flow of attacks, the rationales offered by strategists and attackers, and the ways in which suiciders are recruited. They observe repeatedly, and convincingly, that suicide attacks follow from the military presence and influence of foreign forces, military and political, in the homelands of the attackers. The occupiers are the United States and its allies in Iraq and Afghanistan, and U.S. policies toward the Pakistani government, one that is illegitimate in the eyes of Islamists. In Lebanon and Israel/Palestine, the occupiers and targets of suicide attacks are or have been Israelis. In Chechnya, the targets have been Russians and their local allies; in Sri Lanka, the Sinhalese who occupy the Tamil homeland of Eelam.

The militants directing these suicide campaigns have said they use the strategy because it is the most effective means for inducing the occupiers to withdraw. In this they sometimes reference the 1983 bombing of the barracks of U.S. and French forces in Beirut that led to the withdrawal of international peacekeeping forces. And the testimony of the suiciders themselves converges with the strategic thinkers: Over and over again, in testimony before their attacks and in conversations with their friends and families, they explain their martyrdom as attacks on hated occupiers of their homelands. There is often a personal motivation as well, in which revenge reinforces or substitutes for jihadist doctrine. Between 30,000 and 40,000 civilians were killed in Russia's Chechen War of 1999–2004. A number of the women suicide bombers—21 of 63 were women—were known to have sought revenge against Russians who had killed family members. A rare interview study of family members concluded that 82% of Chechen bombers, of both genders, were secular before some traumatic event, such as the killing of a close family member, set them on the path to martyrdom.

In general, Pape and Feldman give little weight to the role of universal Islamic jihad. Yet they acknowledge that the religious difference between the West and Islamic countries is a fundamental background condition, one that intensifies the sense of violation and adds to the cultural justification for suicide attacks. Moreover, they point out that suicide bombings are virtually unknown in Islamic countries, even the most conservative, unless prompted by the presence of foreign military forces and by political influence on corrupt local regimes. On the other hand, this reviewer observes that there is nothing deterministic about foreign occupation in combination with religiocultural difference. More than 60 years of Han Chinese occupation of Tibet have not prompted suicide bombings but, rather, suicide immolations, suggesting that the content of religious doctrine and leadership strategies are key elements in the causal chain to suicide bombings.

The transnational suicide bombings carried out in the United States on September 11, 2001, and in London and Madrid a few years later also are analyzed in Pape and Feldman's framework. The perpetrators all identified strongly with their Islamic homelands and sought vengeance on those who occupied it. They went through a mostly self-induced process of intense interaction among themselves, withdrawal from the larger societies in which they lived, and a commitment to suicide attacks with the explicit aim of striking back at those who violated their countries of origin..

Pape and Feldman so emphatically reject the idea of a universal jihadist crusade against the West that their own explanation of suicide bombings sometimes seems just as monocausal. But it is not. Foreign occupation by a religiously and culturally distinct power is the most important factor, not the only one. It is clear that the ideological content of conservative Islam, Salafist or otherwise, provides strong sanctions for acting against “infidels” in defense of the imagined global Islamic community. This identity provides a rationale for suicide attackers and ensures the support of many of their families and community, and the celebration of their martyrdom. The strategic calculations by militant leaders are just as important: Suicide attacks have become part of what Charles Tilly would have called the repertoire of political action for insurgents resisting oppression by “crusaders” and their inheritors. And the utility of the strategy in their cases contributes to its proliferation elsewhere.

Both the U.S. withdrawal from Iraq and the Syrian civil war occurred after the period studied by Pape and Feldman. How well does their theory contribute to our understanding of recent events in these violence-wracked countries? The lack of a foreign presence in Syria may help explain why so few suicide attacks occurred during the first two years of civil war. The authors' theory also can be stretched to account for the continuation of suicide bombings in Iraq after the withdrawal of U.S. troops. In other settings, the withdrawal of foreign forces has almost invariably led to a sharp decline in suicide attacks. Current suicide bombings in Iraq are almost entirely directed against Shi'ites and the Shi'ite-dominated government, and attributed to Al Qaeda in Iraq or other Sunni jihadists. The reasons seem clear enough: In Salafist doctrine, the Shi'is are heretics, and moreover they “occupy” political space that once was under Sunni rule. And, strategically, it would be plausible for Iraqi jihadists to conclude that since suicide attacks were instrumental in the withdrawal of the Western “crusaders,” they therefore should be effective against the Baghdad regime.

In Deterring Terrorism, two Swiss scholars assembled a group of researchers working on the fourth wave of deterrence theory with experts on terrorism like Brian Jenkins and Martha Crenshaw. The “fourth wave” refers to the uses of deterrence in the post–Cold War world and, specifically, in Jeffrey W. Knopf's chapter, to the possibility of deterring terrorism. The difficulty, as most of the contributors acknowledge in diverse ways, is that deterrence theory does not apply well to terrorism. That is, terrorist strategists are not likely to be deterred by the fear of the countercoercion that might be brought to bear on them. Jihadists operate in a different cultural frame of reference in which deterrence threats may well be an incentive to attack. Janice Gross Stein makes a strong theoretical argument that rational-choice models of deterrence are seriously flawed: “[T]he risk propensities of leaders of insurgency or terrorist organizations in an asymmetrical conflict are likely to be very different from those defending the status quo” (p. 55).

Crenshaw demolishes the logic of U.S. foreign policy against terrorists' use of weapons of mass destruction (WMD), a risk that is the focus of her chapter and three others. The policy was formulated by the George W. Bush administration in 2008, was carried forward by the Obama administration, and relies on the promise of massive retaliation against any WMD use against the United States and its allies. But the logic of classic deterrence theory relies on the capacity to provide precisely calibrated responses to hostile actions, and also implies a willingness to coexist with the antagonist. It strains credulity to think that the diffuse threat of massive deterrence might be effective against opponents with “no fixed address” who operate in a different cultural frame of reference. In practice, U.S. policy is to punish and destroy terrorist organizations. Examination of Al Qaeda objectives makes it clear that their supporters would “coexist” with the West only if all military and political presence in the Islamic world were withdrawn. Deterrence might be effective only against governments that could provide terrorists with WMD.

In contrast to such reliance on deterrence theory, Pape and Feldman's core recommendation is that the United States should “reduce the reliance on foreign occupation as a principal strategy for ensuring national interests” (p. 331). They point out that over 90% of all suicide attacks have become anti-American. The “Occupiers' Dilemma” is that the longer foreign forces are on the ground, the more likely it is that they become the provocation and target for terrorist attacks. On the other hand, such attacks are very likely to subside if, where, and when the United States no longer relies on “boots on the ground” to attain its policy goals in the Islamic world. Military resources should be stationed offshore and, if deployed at all, should remain as briefly as possible.

Why deterrence theory, with its assumptions about rationality in Western political contexts, is not likely to be effective against terrorism in Islamic and other non-Western contexts is more readily understood from the perspective of Salafist and jihadist texts. They make clear the fundamentally different ideological basis of Islamic activism that guides strategic thought and motivates suicide bombers. Both Crenshaw and Stein point out, in their essays in Deterring Terrorism, that ideological and cultural values in the Islamic world contradict basic assumptions of Western deterrence theory. Yet in none of the books under review, except for a discussion in McAlister and Schmid's overview of theories of terrorism (Handbook, pp. 222–26), is there any discussion of Salafist writings and the strategic guidance derived from them. For in-depth discussions, one must look elsewhere, for example, to Quintan Wiktorowicz, “Anatomy of the Salafi Movement,” Studies in Conflict & Terrorism 29 (2006): 207–39; the writings of the French scholar Gilles Keppel, in Beyond Terror and Martyrdom: The Future of the Middle East (trans. Pascale Ghazale, 2008); and the English analyst Alison Pargeter, in The New Frontiers of Jihad: Radical Islam in Europe (2008). In this reviewer's judgment, these are essential complements to the rationalist and strategic analyses that dominate the three books reviewed here. It is, after all, implausible to think that one might formulate effective doctrines of counterterrorism without understanding the motives, perceptions, and cultures of the terrorists and the environments in which they live.

If we take a broader view, terrorism is a doctrine and a strategy (or tactic) that links closely to the larger field of political conflict analysis. So it is worth repeating McAlister and Schmid's observation, quoted previously, that a general theory of terrorism needs to be placed within a more comprehensive theory of political action. Such a theory would look at political militancy across multiple levels of analysis and identify the circumstances, and ideologies, that shape militants' choices of political strategies. Several of the contributors to Deterring Terrorism point in this direction when they say that terrorists should be presented with alternative courses of action. More generally, international policies and political environments could be designed in ways that might divert militants from deadly strategic choices.