"A democracy as resilient as ours must reject the false choice between our security and our ideals," President Obama said on April 16, "and that is why these methods of interrogation are already a thing of the past."

But is it really a false choice? It’s certainly tempting to think so. The fashionable assumption that coercive interrogation (up to and including torture) never saved a single life makes it easy to resolve what otherwise would be an agonizing moral quandary.

The same assumption makes it even easier for congressional Democrats, human-rights activists, and George W. Bush-hating avengers to call for prosecuting and imprisoning the former president and his entire national security team, including their lawyers. The charge: approving brutal methods — seen by many as illegal torture — that were also blessed, at least implicitly, by Nancy Pelosi, now the House speaker, and other Intelligence Committee members in and after 2002.

But there is a body of evidence suggesting that brutal interrogation methods may indeed have saved lives, perhaps a great many lives — and that renouncing those methods may someday end up costing many, many more.

To be sure, the evidence in the public record is not conclusive. It comes mainly from Bush appointees and Central Intelligence Agency officials with records to defend and axes to grind. There is plenty of countervailing evidence coming from critics who have less access to the classified information that tells much of the story and have their own axes to grind. There are also plausible arguments for renouncing coercive interrogation even if it does save some lives.

But it would be an abdication for the president to proceed on the facile assumption that his no-coercion executive order is cost-free. Instead, he should commission an expert review of what interrogators learned from the high-value detainees both before and after using brutal methods and whether those methods appear to have saved lives. He should also foster a better-informed public debate by declassifying as much of the relevant evidence as possible, as former Vice President Cheney and other Republicans have urged.

The CIA’s post-9/11 records are probably the most instructive body of empirical evidence in existence as to the relative effectiveness of gentle and harsh interrogation methods. The Senate Intelligence Committee is looking into this data. But its review could be skewed by the committee’s own prior role and its current incentives to reach politically palatable conclusions. We need the person responsible for protecting us to direct an unblinking, unbiased review of whether lives were saved.

The review should start by taking seriously the views of the people with the most-detailed knowledge. They say that the coercive interrogation program was highly effective.

Michael Hayden, Bush’s last CIA director, and former Attorney General Michael Mukasey recently wrote, "As late as 2006, fully half of the government’s knowledge about the structure and activities of Al Qaeda came from those interrogations." Former CIA Director George Tenet has said, "I know that this program has saved lives. I know we’ve disrupted plots. I know this program alone is worth more than [what] the FBI, the [CIA], and the National Security Agency put together have been able to tell us." Former National Intelligence Director Mike McConnell has said, "We have people walking around in this country that are alive today because this process happened."

Of course, those four have a stake in defending the actions of themselves and other Bush appointees by magnifying the benefits. But I see little reason to doubt their sincerity, or that of the former senior CIA official who told my colleague Shane Harris anonymously that he was "certain" that the CIA "prevented multiple attacks" thanks to the coercive interrogations. (See "Reading a Torture Memo.")

I see no reason at all to doubt the sincerity of Dennis Blair, Obama’s own national intelligence director, who said in an April 16 memo to his staff that "high value information came from interrogations in which those methods were used and provided a deeper understanding" of Al Qaeda.

Blair later qualified this by adding, "There is no way of knowing whether the same information could have been obtained through other means." But a reasonable person might imagine that it would take more than sweet talk, mind games, and lollipops to get hardened terrorists to sing.

"I like to think I would not have approved those methods in the past," Blair added, "but I do not fault those who made the decisions at that time." His honesty is commendable. In this fevered town, in this bitter time, Blair’s empathy for former officials who went to extremes to protect the country could bring a mob to his door carrying "war criminal" signs.

One of the most specific CIA claims that the brutalizing of detainees averted a planned attack, as described in speeches by then-President Bush and in one of the recently released Justice Department documents, goes like this:

After being subjected to waterboarding and other brutal methods in 2002, Abu Zubaydah explained that he and his "brothers" were permitted by Allah to yield when interrogators pushed them to the limit of their endurance. At that point, he provided information that helped the CIA capture Ramzi Binalshibh. The two captives then gave up details that led to the capture of Khalid Shaikh Mohammed (KSM, in official shorthand), whom Zubaydah had identified as the mastermind of the 9/11 attacks. KSM, in turn, was initially defiant but — after being tormented and waterboarded more than 100 times — gave up information leading to the capture of a terrorist named Zubair, and then to the capture of Hambali, leader of Al Qaeda’s Southeast Asian affiliate Jemaah Islamiyah, and then to his brother "Gun Gun" in Pakistan, whose information led to a cell of 17 Southeast Asian terrorists.

Did tough interrogations prevent terrorists from crashing a hijacked airliner into the tallest building in Los Angeles?

This chain of events, the CIA insists, unraveled the dangerous "Second Wave" plot, planned by KSM and Hambali, that called for the Southeast Asian terrorists to crash a hijacked airliner into the tallest building in Los Angeles, the Library Tower.

There is also evidence cutting against the CIA’s claims. A.B. Krongard, who was the agency’s executive director when the coercive interrogations began, told author Ron Suskind that KSM and other Qaeda captives "went through hell and gave up very, very little." Former FBI agents have claimed that their conventional, non-coercive interrogation got better information out of Zubaydah than the CIA did with its tough stuff.

Many experienced military and FBI interrogators say they’ve never used coercion, contending that it doesn’t work because prisoners will say anything to stop the pain. (But how would they know it doesn’t work, not having tried it? And if you were a terrorist desperate to stop the pain, would you fabricate a story that your interrogators would likely consider suspect — or tell them where to find other terrorists?)

There are also reports of disagreement within the intelligence community as to the seriousness of the Second Wave plot. Maybe it would have fizzled even without coercive interrogations.

But maybe not. As former Bush speechwriter Marc Thiessen has written, if the 9/11 plot had been thwarted, Bush’s critics "would be telling us how it was never really close to execution and [that] men armed with nothing more than box cutters [could never] hijack four airplanes simultaneously and fly them into buildings."

The bottom line about the effectiveness of brutal interrogations, Blair has asserted, is that "these techniques have hurt our image around the world" so much that "the damage they have done to our interests far outweighed whatever benefit they gave us, and they are not essential to our national security."

He may be right (or wrong) about that. But even if he is right, does it make sense not only to ban the brutal Bush-Cheney brand of interrogation but also to lurch to the opposite extreme by ordering the CIA not to "threaten or coerce" any detainee in any way?

No yelling? No restricting a detainee to nutritious but unappetizing cold food until he talks? No threats of long-term incarceration, even though such are used routinely and quite legally by police all over America? Should people suspected of plotting mass death really be treated more punctiliously than people suspected of burglary?

Not in the view of a veteran prosecutor who suggested somewhat ambiguously in 2002 that terrorists are not "entitled to the protection of the Geneva Convention" and that we need to "find out what their future plans might be, where other cells are located."

That was Eric Holder, whose policy now, as Obama’s attorney general, is to give full Geneva Convention protection to terrorists who may be plotting mass murders while considering whether to prosecute Bush appointees for going too far in their desperate zeal to save lives.

This article appeared in the Saturday, April 25, 2009 edition of National Journal.