News media credibility has suffered another wound, thanks to an item in the Periscope section of Newsweek magazine’s May 9 issue.

Newsweek has retracted the item, which said government investigators had confirmed reports of “interrogation abuses,” including desecration of the Quran, Islam’s holy book. Mainstream media critics have jumped on the retraction, saying it unmasks a reckless institution bent on spreading lies that discredit the Bush administration and embarrass the United States. Some leapt to the conclusion that Newsweek’s mea culpa demonstrates the abuse claims are untrue.

The weekly news magazine could have avoided much of this by using more journalistic caution. Told by an informed but unnamed source that investigators had come up with evidence of misconduct, the magazine showed what it had to two Defense Department officials and asked for their comment. Neither of them disputed the reference to a copy of the Quran having been flushed down a toilet, and Newsweek noted: “An Army spokesman declined to comment.”

The toilet incident was a major part of the Newsweek story. As Editor Mark Whitaker said in his explanation, allegations of such actions had circulated for a couple of years, but this was the first time government investigators were said to have confirmed them. Had the magazine asked Defense Department officials to comment specifically on that aspect, it would have been on more solid ground.

Newsweek didn’t take that step, however, and now it is being likened to CBS and former network anchor Dan Rather’s handling of a later discredited story about President Bush’s National Guard record.

To fully understand the damage done by Newsweek’s lapse, it is important to keep in mind the dimensions of that lapse.

The Periscope item reported that investigators looking into the prisoner abuse allegations had confirmed some incidents and that those findings would be included in a report being prepared by the U.S. Southern Command, which oversees the detention center at Guantanamo Bay in Cuba.

After publication, anti-American rioting broke out in several Afghanistan cities and elsewhere in the Islamic world, resulting in about 15 deaths. Subsequently, a Pentagon spokesman told Newsweek that the investigation it mentioned was, in Whitaker’s words, “never meant to look into charges of Quran desecration.” And Newsweek’s anonymous source then said the information he saw might not have been in that report but in other investigative documents.

Many administration officials, including White House spokesman Scott McClellan, are now implying that the backpedaling by Newsweek confirms that all U.S. personnel are meticulously honoring official U.S. policy requiring respect of the Quran. And that allegations to the contrary are therefore false. As recently as this week, former prisoner Abdul Rahim asserted on Afghan television that desecration of the Quran was common during his years in detention.

To play its proper role in a democratic system, a free and independent press needs to preserve its credibility. Errors that discredit the watchdog not only misinform the public, they enable government officials to escape oversight.

Newsweek earned its lumps and needs to accept them. But that doesn’t lessen the need to keep a spotlight on the government’s conduct of the war, including its treatment of prisoners.