The following editorial appeared in the Chicago Tribune on Wednesday, Aug. 26:

Almost eight years ago, jetliners slammed into the World Trade Center towers and the Pentagon. Americans, in their rage and grief, demanded to know who had attacked them. And they expected their government to do everything in its power to prevent another attack, which everyone thought was imminent. In the months after Sept. 11, 2001, American interrogators had an urgent mission: Extract information from terrorism suspects about future attacks as quickly and effectively as possible.

Justice Department lawyers scrambled to make clear which interrogation techniques were permitted and which weren’t. What was torture and what wasn’t. Those guidelines, however, were often vague and could be interpreted in different ways, or misinterpreted.

Some investigators used techniques such as waterboarding — simulated drowning — that were later judged to be torture.

We also know that interrogations disrupted terrorist activity. A 2004 Central Intelligence Agency inspector general’s report made public Monday concluded that the agency’s “detention and interrogation of terrorists has provided intelligence that has enabled the identification and apprehension of other terrorists and warned of terrorist plots planned for the United States and around the world.”

But the release of that report provided fresh details about interrogation techniques that may have crossed the legal line.

CIA interrogators threatened to kill the children of Sept. 11 mastermind Khalid Shaikh Mohammed. This was after they tried “non-aggressive” techniques and concluded that Mohammed was “withholding imminent threat information.”

Interrogators revved a power drill while another prisoner was naked and hooded. He was warned that if he did not talk, “we could get your mother in here.” One interrogator choked a captive until he almost passed out, and then was shaken and revived.

On Monday, Attorney General Eric Holder opened a preliminary investigation into whether CIA operatives broke the law in those coercive interrogations of suspected terrorists. He named federal prosecutor John Durham to lead the investigation.

Holder took pains to call this a “preliminary review.” Durham will determine whether a full-scale criminal investigation of CIA employees is warranted. Holder said that such a review does not mean that charges will automatically follow.

It’s good, at least, that Holder didn’t go the path of appointing an independent prosecutor with unfettered powers. The scope of Durham’s investigation appears to be narrow. It’s also good that Holder and President Barack Obama have said that CIA agents who operated in good faith on what they believed to be legal grounds won’t be prosecuted.

But some Democratic leaders are still pressing for a broader investigation of how this nation responded to the Sept. 11 attacks. And even the task the attorney general has given Durham could have a chilling effect on the work of CIA investigators.

Yes, you hear former Vice President Dick Cheney and other GOP leaders saying that. But even if you want to chalk that up to politics, you can’t ignore the warnings that have been sounded by CIA Director Leon Panetta, a Democrat and former congressman. Panetta says we need to move on.

“This is in many ways an old story. … The use of enhanced interrogation techniques, begun when our country was responding to the horrors of Sept. 11, ended in January,” he said after Monday’s release of the 2004 report. “For the CIA now, the challenge is not the battles of yesterday, but those of today and tomorrow. It is there that we must work to enhance the safety of our country. That is the job the American people want us to do.”

That’s in keeping with what Panetta said earlier this year when the drumbeat in Congress for investigations was growing. He urged Congress to “stay focused on the present, to stay focused on the future and to stay focused on those things that may threaten the United States of America.”

The Durham investigation focuses on the past — and looms as a huge distraction or worse.

Eight years after the trauma of those terrorist attacks, it’s easy to see that some interrogators were overzealous. But a long-running backward-looking political-score-settling probe could chill CIA interrogators and all of those on the front lines of keeping America safe now. Those agents can’t do their jobs effectively if they’re worried about being criminally charged, years later, for actions they were told at the time were legal, actions that were encouraged by superiors in a moment of national crisis.

In many ways the Obama administration has been careful about its approach to national security. It has not automatically rejected controversial Bush-era practices.

Obama, to the shock of some human rights activists, has decided to continue the practice of rendition – shipping terrorism suspects to other, typically rougher governments for detention and interrogation. Started under President Bill Clinton and used often by Bush, the practice is seen by critics as a way to evade the niceties of U.S. law. Obama has apparently decided that it is critical to our security.

Obama, we expect, has granted Holder the independence to make decisions such as the one he announced on Monday. That’s what a president should do. But it sounds to us like the attorney general made a poor decision.

One day, heaven forbid, there may be another attack on American soil. Once again, we will ask CIA and other agents to find out whatever they can, as quickly as possible, to defend this nation. How will they respond?