We use response curves in a repeated game to analyze key aspects of mutual deterrence: escalation, de-escalation, incomplete deterrence, and deterrence by denial. In this approach, episodes of violence are due to interacting response curves, which disincentivize opponents from attacking through both deterrence and compellence. Both sides punish attacks to maintain credibility in future episodes, disincentivizing larger attacks and yielding nonviolent lulls. We empirically estimate those curves using detailed incident data from the Israel-Gaza conflict between 2007 and 2017. Our estimates match the dynamics of the raw data: very frequent episodes of low lethality violent exchange. Response curves are stable and probably Markovian. They exhibit a posture consistent with incomplete deterrence: i.e., episodes de-escalate, but to a violent equilibrium. Israeli missile defense shifts the Gazan response curve to a less aggressive posture, as predicted by theory.

This paper studies the long-term effects of politically motivated violence on individuals’ political attitudes focusing on the Second Intifada (2000 – 2005). We conduct a large-scale survey that measures Israelis’ attitudes today and elicits their places of residence since 1985. The survey allows us to measure individuals’ direct exposure to terrorism and to account for potential selective migration. This, in combination with the fact that individuals’ characteristics are balanced with respect to their exposure to terrorism, enables us to overcome identification concerns and provide credible estimates of the causal effects of the Intifada on attitudes. The results indicate that exposure to terrorism during the Second Intifada caused a persistent and substantial shift toward right-wing attitudes that is still observable two decades later. Thus, our analysis provides systematic empirical evidence supporting the view that the Second Intifada soured a generation of Israelis on the idea of peace.

This paper assesses the validity of narrow deterrence theory between a State and a Non-State actor in the context of the Israel and Gaza conflict.  We build the most comprehensive data set on this conflict between 2007 and 2014 using original security reports from the United Nations, which capture over 16,000 Palestinian projectile launches and over 8,800 Israeli airstrikes, recorded with precise timing. We show that this conflict is characterized by short-lived episodes of violence separated by quiet interludes. Episodes tend to last less than one day and are followed by 3.5 days of calm, on average. Most episodes have no retaliation and consist only of provocations that go unanswered. Moreover, counter-retaliation does not induce subsequent episodes. We find that Israeli retaliation strongly correlates with Gazans’ initial number of attacks and type of rockets fired. Yet, rather than provoking an immediate increase in violence or de-escalation, retaliation seems to have no short-term effect. These findings support the concept of narrow deterrence and weigh heavily against the argument that retaliation perpetuates this conflict.

Conflict points around the world involve government forces fighting terrorist groups. In this type of warfare, there is a danger that counterterrorist efforts may backfire, providing ammunition for additional cycles of violence. We study this issue focusing on selective and indiscriminate house demolitions employed by Israel during the Second Intifada. We exploit the temporal and spatial variation of this policy to assess its impact on Palestinians’ political views. We find that the civilian population does not react to punitive house demolitions, a selective form of counterterrorism. On the contrary, Palestinians are more likely to adopt more radical political opinions in response to precautionary house demolitions, an indiscriminate form of counterterrorism. We also show that political radicalization induced by indiscriminate counterterrorism leads to an increase in future terror attacks. Overall, our analysis provides explicit empirical support to the mechanism behind the positive correlation between indiscriminate counterterrorism and future levels of violence.

This paper provides the first systematic analysis of the link between economic, political, and social conditions and the global phenomenon of ISIS foreign fighters. We find that poor economic conditions do not drive participation in ISIS. In contrast, the number of ISIS foreign fighters is positively correlated with a country's GDP per capita and Human Development Index (HDI). In fact, many foreign fighters originate from countries with high levels of economic development, low income inequality, and highly developed political institutions. Other factors that explain the number of ISIS foreign fighters are the size of a country's Muslim population and its ethnic homogeneity. Although we cannot directly determine why people join ISIS, our results suggest that the flow of foreign fighters to ISIS is driven not by economic or political conditions but rather by ideology and the difficulty of assimilation into homogeneous Western countries. These conclusions are consistent with those of the related qualitative literature that relies on the personal profiles of a small and selected sample of ISIS foreign fighters.

This paper investigates whether the 9/11 attacks affected the assimilation rate of Muslims in the United States.  Terror attacks by Islamic groups are likely to induce a backlash against Muslims, thereby raising their costs of assimilation. We find that Muslim immigrants living in states with the sharpest increase in hate crimes also exhibit: (i) greater chances of marrying within their own ethnic group; (ii) higher fertility; (iii) lower female labour force participation; and (iv) lower English proficiency. These findings shed light on the increasing use of terror and concurrent rise in social tensions surrounding Muslim immigrants in the West.

This paper investigates whether attacks against Israeli targets help Palestinian factions gain public support.  We link individual level survey data to the full list of Israeli and Palestinian fatalities during the period of the Second Intifada (2000-2005), and estimate a flexible discrete choice model for faction supported.  We find some support for the “outbidding” hypothesis, the notion that Palestinian factions use violence to gain prestige and influence public opinion within the community.  In particular, the two leading Palestinian factions, Hamas and Fatah, gain in popularity following successful attacks against Israeli targets.  Our results suggest, however, that most movement occurs within either the secular groups or within the Islamist groups, but not between them.  That is, Fatah’s gains come at the expense of smaller secular factions while Hamas’ gains come at the expense of smaller Islamic factions and the disaffected.  In contrast, attacks by the Palestinian Islamic Jihad lower support for that faction.

This paper examines whether house demolitions are an effective counterterrorism tactic against suicide terrorism. We link original longitudinal micro-level data on houses demolished by the Israeli Defense Forces with data on the universe of suicide attacks against Israeli targets. By exploiting spatial and time variation in house demolitions and suicide attacks during the second Palestinian uprising, we show that punitive house demolitions (those targeting Palestinian suicide terrorists and terror operatives) cause an immediate, significant decrease in the number of suicide attacks. In contrast, Palestinian fatalities do not have a consistent effect on suicide terror attacks, while curfews and precautionary house demolitions (demolitions justified by the location of the house but unrelated to the identity of the house's owner) cause a significant increase in the number of suicide attacks. The results support the view that selective violence is an effective tool to combat terrorist groups and that indiscriminate violence backfires.

This paper examines how violence influences the political preferences of an aggrieved constituency that is purportedly represented by militant factions. Using longitudinal public opinion poll micro data of the Palestinian population linked to data on fatalities from the Second Intifada, we find that although local Israeli violence discourages Palestinians from supporting moderate political positions, this “radicalization” is fleeting, and vanishes completely within 90 days. We do, however, find evidence suggesting that collateral violence affecting Palestinian civilians has a stronger effect on the populations’ political preferences relative to individuals directly targeted by the Israeli military.  In addition, we observe that major political events in the Palestinian-Israeli conflict have had a longer-term impact on political preferences. Individuals who were teenagers during the period of the Oslo negotiations tend to have relatively moderate preferences, while those who were teenagers during the First Intifada tend to be relatively radical.

This article analyzes the link between economic conditions and the quality of suicide terrorism.  While the existing empirical literature shows that poverty and economic conditions are not correlated with the quantity of terror, theory predicts that poverty and poor economic conditions may affect the quality of terror.  Poor economic conditions may lead more able and better-educated individuals to participate in terror attacks, allowing terror organizations to send better-qualified terrorists to more complex, higher-impact terror missions.  Using the universe of Palestinian suicide terrorists who acted against Israeli targets in 2000–2006, we provide evidence of the correlation between economic conditions, the characteristics of suicide terrorists, and the targets they attack.  High levels of unemployment enable terror organizations to recruit better educated, more mature, and more experienced suicide terrorists, who in turn attack more important Israeli targets. 

A large number of studies show that war and terrorism have a significant effect on individuals’ political attitudes.  Yet, this extensive literature does not inspect the mechanisms behind this effect.  This paper concentrates on one possible mechanism, by differentiating between the human toll of terror and war and the economic costs they cause.  For these purposes we focus on the Israeli-Palestinian conflict, and use variation in the level of violence across time and space together with localities’ different exposure to the tourism sector to estimate their respective effects on political attitudes.  Our results suggest that whereas fatalities from the conflict make Israelis more willing to grant territorial concessions to the Palestinians, the associated economic costs of conflict do not have a consistent significant effect on individuals’ political attitudes. 

This paper analyzes the impact of terrorism on Israeli companies related to the defense, security or anti-terrorism industries, relative to its impact on the rest of the companies. We match every Israeli company to the American company with the closest expected return among all the companies that belong to the same industry and trade in the same market in order to isolate the effect of terrorism from other common industry shocks. The findings show that whereas terrorism had a significant negative impact of 5% on non defense-related companies, it had a significantly positive overall effect of 7% on defense-related companies.

The literature on conflict and terrorism has paid little attention to the economic costs of terrorism for the perpetrators. This paper aims to fill that gap by examining the economic costs of harboring suicide terror attacks. Using data covering the universe of Palestinian suicide terrorists during the second Palestinian uprising, combined with data from the Palestinian Labor Force Survey, we identify and quantify the impact of a successful attack on unemployment and wages. We find robust evidence that terror attacks have important economic costs. The results suggest that a successful attack causes an increase of 5.3 percent in unemployment, increases the likelihood that the district’s average wages fall in the quarter following an attack by more than 20 percent, and reduces the number of Palestinians working in Israel by 6.7 percent relative to its mean. Importantly, these effects are persistent and last for at least six months after the attack.