Is torture ever permissible? The U.S. is in the midst of a great debate on this subject as the exigencies of counterterrorism collide with peacetime norms and traditions. But if inflicting pain during an interrogation is highly controversial, what about inflicting death before an interrogation?

We do this all the time on the battlefield, where killing enemy combatants before they kill us is accepted as the ordinary course of war. But now we are engaged in a shadow war off the battlefield, against terrorists who do not wear uniforms and operate in stealth. Is it permissible to strike them before they strike us?

Let me be more specific. In 1981, Ronald Reagan promulgated Executive Order 12333, which, among other provisions, declared that “No person employed by or acting on behalf of the United States Government shall engage in, or conspire to engage in, assassination.” This had been preceded by similar such restrictions issued by Presidents Ford and Carter.

These assassination bans, as the 9/11 Commission report makes clear, came to hamstring our policy against al Qaeda in the late 1990’s. After Osama bin Laden had successfully launched terrorist attacks against American embassies in Kenya and Tanzania, the CIA was ordered to find ways to put al Qaeda out of business. Elaborate plans were drawn up, but the assassination ban dominated the agency’s thinking; the upshot of all the preparations, states the 9/11 Commission staff report, was that “the only acceptable context for killing bin Laden was a credible capture operation.”

A plan designed to kill bin Laden outright was deemed unacceptable and illegal. Never mind that the U.S. had launched a fusillade of cruise missiles at one of his camps in 1998 to do just that; that was a military action, not a CIA covert operation.

One of the most memorable sentences in the entire 9/11 Commission report concerns the CIA contemplating action against bin Laden on a road leading to the Afghan city of Kandahar. James Pavitt, the assistant head of the CIA’s Directorate of Operations, “expressed concern that people might get killed; it appears he thought the operation had at least a slight flavor of a plan for an assassination.”

Not long afterward, the operation was called off. As a result, people did get killed—thousands of them—and not on the road to Kandahar but in lower Manhattan, at the Pentagon, and in rural Pennsylvania.

Islamist clerics around the world are still calling for suicide bombers to attack the United States. Jane Perlez of the New York Times reports on one such Pakistani cleric in today’s paper. If the CIA could from time to time engage in covert action against such avowed advocates of violence against the U.S., would they be so brazen? Would the madrassas in which they preach their hatred continue to be multiplying homicidal graduates?

President Bush can revoke the assassination ban at will. As the Congressional Research Service explains, he can most obviously do so by issuing a new Executive Order. As the CRS also points out, under certain circumstances, like an attack or an impending attack on the United States, such an Executive Order need not be published. In other words, Bush might already have revoked the ban and we would not know it—at least until homicidal clerics start disappearing.