Killer instincts: Why suicide bombers do it

Four years ago, the late Susan Sontag was excoriated for arguing, in a brief New Yorker piece, that the attacks that brought down the World Trade Center were inspired not by hatred of ''civilization" or ''the free world," but rather by opposition to ''specific American alliances and actions." Today that argument– seen by hawks in those dark post-September 11 days as treasonously empathetic– has become a commonplace in the latest political science work on terrorism.

No one, for example, is hurling charges of crypto-treason at Robert A. Pape, an associate professor of political science at the University of Chicago known for hard-nosed studies of air power in wartime. But Pape's new book, Dying to Win: The Strategic Logic of Suicide Terrorism (Random House), which grew out of a much-cited 2003 article in the American Political Science Review, is a prime example of the mainstreaming of Sontag's once-villified view.

''Suicide terrorism is a response to occupation," Pape says in a phone interview. ''Islamic fundamentalism has very little to do with it."

Dying to Win draws on a thorough database of all suicide attacks recorded since the contemporary practice was born during the Lebanese civil war in the early 1980s: a total of 315 incidents through 2003, involving 462 suicidal attackers. Of the 384 attackers for whom Pape has data– who committed their deeds in such danger zones as Sri Lanka (where the decidedly non-fundamentalist, quasi-Marxist Tamil Tigers have used suicide attacks since 1987 in their fight for a Tamil homeland), Israel, Chechnya, Iraq, and New York– only 43 percent came from religiously affiliated groups. The balance, 57 percent, came from secular groups. Strikingly, during the Lebanese civil war, he says, some 70 percent of suicide attackers were Christians (though members of secular groups).

The thrust of his argument is that suicide terrorism is an eminently rational strategy. Everywhere it has been used, the countries that face it make concessions: the United States left Lebanon; Israel withdrew from Lebanon and now (much of) the West Bank; and Sri Lanka gave the Tamils a semiautonomous state.

Since occupation spurs terrorism, Pape concludes that America should ''expeditiously" (but not recklessly) withdraw troops from Iraq. It should also reduce its energy dependence on the Middle East, refrain from posting troops in the Gulf States, and return to a strategy of balancing the Middle Eastern countries against one another from afar–policy prescriptions that have inspired criticism apart from his social science. (''Wouldn't [Pape's recommendations] be the ultimate concession to the suicide strategy?" Martin Kramer, a specialist in Middle Eastern studies, asked after the 2003 article appeared.)

In the views of some critics, Pape's original article erred by dismissing all talk of religious or cultural factors in suicide bombings. If suicide attacks were a universally rational weapon of the weak, the critics argued, we would see them everywhere– and we don't.

In fact, in a fascinating contribution to the new essay collection ''Making Sense of Suicide Missions" (Oxford), the Yale political scientist Stathis Kalyvas and a Spanish colleague, Ignacio Sanchez Cuenca, point out that FARC, the Columbian rebel group, once hatched a plan to fly a plane into that country's presidential palace but could find no willing pilot, even after dangling an offer of $2 million for the pilot's family. In addition, the Basque group ETA has rejected offers from its members to blow themselves up for the cause.

But in the book, Pape reconsiders those cultural factors: suicide bombing, he now writes, is most likely to happen when the occupying force and the ''occupied" insurgents are from different religious backgrounds. (The Tamil minority in Sri Lanka are mostly Hindu and Christian; the Sinhalese majority are Buddhists.)

Research by other scholars backs up this point. David Laitin, a Stanford University expert on civil wars, and Eli Berman, an economist at the University of California at San Diego, have demonstrated that while only 18 percent of the 114 civil wars since 1945 have pitted members of one religious group against another, fully 90 percent of suicide attacks take place in inter-religious conflicts.

Laitin and Berman, too, view suicide terrorism as following impeccable game-theory logic: When your targets are ''hard" and the enemy is wealthy, well armed, and possessed of good intelligence, they write, suicide bombing begins to make sense as a strategy.

However, Diego Gambetta, an Oxford University sociologist and the editor of Making Sense of Suicide Missions, thinks these claims of rationality among self-immolators go a bit too far. First, do the attacks achieve as much as Pape contends? Israel had already committed to pulling out of the West Bank under the Oslo accords when a fresh wave of attacks came in 1994 and 1995. Far from causing the withdrawal, he argues, the attacks may in fact have heightened Israeli resistance to it.

Then there's the question of Islam. There may be non-Islamic suicide bombers, Gambetta writes. But ''we do not have even a single case of a non-Islamic faith justifying" suicide missions.

Gambetta makes a tentative cultural-historical argument, tracing the suicidal impulse in the Middle East back to the Iran-Iraq war, when thousands of fundamentalist Iranian soldiers marched into certain death against Iraqi tank formations. That strain of self-sacrifice then spread into Lebanon and Palestine and now Iraq, through a badly understood dynamic.

Conflicting theories aside, social scientists have made strides in understanding suicide bombers. Once considered the dregs of the earth (poor, uneducated, sexually starved), they have been shown– by Claude Berrebi, of the RAND Institute, among others– to be, on average, better educated and better off than their countrymen.

Nevertheless, all the work on suicide terrorism has one major, merciful shortcoming: sample size. ''No matter how you count terrorist attacks, we are still well short of 1,000 of these episodes" since 1980, Gambetta says. Hard as it is to believe amid the grim daily dispatches from Iraq, suicide bombing remains, among the infinite numbers of ways humans cause bloodshed, exceedingly rare.

This essay, distributed by the Featurewell service, first appeared in the Boston Globe.