I recently caught a glimpse of the effects of torture in action at an event honoring Maher Arar. The Syrian-born Canadian is the world's most famous victim of "rendition," the process by which US officials outsource torture to foreign countries. Arar was switching planes in New York when US interrogators detained him and "rendered" him to Syria, where he was held for ten months in a cell slightly larger than a grave and taken out periodically for beatings.

Arar was being honored for his courage by the Canadian Council on American-Islamic Relations, a mainstream advocacy organization. The audience gave him a heartfelt standing ovation, but there was fear mixed in with the celebration. Many of the prominent community leaders kept their distance from Arar, responding to him only tentatively. Some speakers were unable even to mention the honored guest by name, as if he had something they could catch. And perhaps they were right: The tenuous "evidence"--later discredited--that landed Arar in a rat-infested cell was guilt by association. And if that could happen to Arar, a successful software engineer and family man, who is safe?

In a rare public speech, Arar addressed this fear directly. He told the audience that an independent commissioner has been trying to gather evidence of law-enforcement officials breaking the rules when investigating Muslim Canadians. The commissioner has heard dozens of stories of threats, harassment and inappropriate home visits. But, Arar said, "not a single person made a public complaint. Fear prevented them from doing so." Fear of being the next Maher Arar.

The fear is even thicker among Muslims in the United States, where the Patriot Act gives police the power to seize the records of any mosque, school, library or community group on mere suspicion of terrorist links. When this intense surveillance is paired with the ever-present threat of torture, the message is clear: You are being watched, your neighbor may be a spy, the government can find out anything about you. If you misstep, you could disappear onto a plane bound for Syria, or into "the deep dark hole that is Guantánamo Bay," to borrow a phrase from Michael Ratner, president of the Center for Constitutional Rights.

But this fear has to be finely calibrated. The people being intimidated need to know enough to be afraid but not so much that they demand justice. This helps explain why the Defense Department will release certain kinds of seemingly incriminating information about Guantánamo--pictures of men in cages, for instance--at the same time that it acts to suppress photographs on a par with what escaped from Abu Ghraib. And it might also explain why the Pentagon approved the new book by a former military translator, including the passages about prisoners being sexually humiliated, but prevented him from writing about the widespread use of attack dogs. This strategic leaking of information, combined with official denials, induces a state of mind that Argentines describe as "knowing/not knowing," a vestige of their "dirty war."

"Obviously, intelligence agents have an incentive to hide the use of unlawful methods," says the ACLU's Jameel Jaffer. "On the other hand, when they use rendition and torture as a threat, it's undeniable that they benefit, in some sense, from the fact that people know that intelligence agents are willing to act unlawfully. They benefit from the fact that people understand the threat and believe it to be credible."

And the threats have been received. In an affidavit filed with an ACLU court challenge to Section 215 of the Patriot Act, Nazih Hassan, president of the Muslim Community Association of Ann Arbor, Michigan, describes this new climate. Membership and attendance are down, donations are way down, board members have resigned--Hassan says his members fear doing anything that could get their names on lists. One member testified anonymously that he has "stopped speaking out on political and social issues" because he doesn't want to draw attention to himself.

This is torture's true purpose: to terrorize--not only the people in Guantánamo's cages and Syria's isolation cells but also, and more important, the broader community that hears about these abuses. Torture is a machine designed to break the will to resist--the individual prisoner's will and the collective will.

This is not a controversial claim. In 2001 the US NGO Physicians for Human Rights published a manual on treating torture survivors that noted: "perpetrators often attempt to justify their acts of torture and ill treatment by the need to gather information. Such conceptualizations obscure the purpose of torture....The aim of torture is to dehumanize the victim, break his/her will, and at the same time, set horrific examples for those who come in contact with the victim. In this way, torture can break or damage the will and coherence of entire communities."

Yet despite this body of knowledge, torture continues to be debated in the United States as if it were merely a morally questionable way to extract information, not an instrument of state terror. But there's a problem: No one claims that torture is an effective interrogation tool--least of all the people who practice it. Torture "doesn't work. There are better ways to deal with captives," CIA director Porter Goss told the Senate Intelligence Committee on February 16. And a recently declassified memo written by an FBI official in Guantánamo states that extreme coercion produced "nothing more than what FBI got using simple investigative techniques." The Army's own interrogation field manual states that force "can induce the source to say whatever he thinks the interrogator wants to hear."

And yet the abuses keep on coming--Uzbekistan as the new hot spot for renditions; the "El Salvador model" imported to Iraq. And the only sensible explanation for torture's persistent popularity comes from a most unlikely source. Lynndie England, the fall girl for Abu Ghraib, was asked during her botched trial why she and her colleagues had forced naked prisoners into a human pyramid. "As a way to control them," she replied.

Exactly. As an interrogation tool, torture is a bust. But when it comes to social control, nothing works quite like torture.

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