For an informed examination on Iraq’s weapons of mass destruction, take a look at an excellent story by Barton Gellman in Wednesday’s Washington Post. The report is a detailed explanation of Iraqi weapons programs of the past, the effectiveness of post-Gulf War U.N. inspections, some of the possible reasons the Clinton and Bush administrations thought Saddam Hussein posed a danger and the direction of the Iraqi weapons programs at the time of the latest war. There are abundant lessons here for all sides in this argument.

The headline tells the “what” of the story: “Iraq’s Arsenal Was Only on Paper.” The “how” and “why” are much more involved. But as David Kay, the hunter of weapons for the Bush administration, discovered, there is nowhere to be found in Iraq large caches of weapons much discussed by the administration, no “grave and gathering danger,” as the president described. “A review of the available evidence, including some not known to the coalition investigators and some they have not made public,” says Mr. Gellman, “portrays a nonconventional arms establishment that was far less capable than U.S. analysts judged before the war.”

With many first-person interviews with Iraqi scientists and examination of original Iraqi weapons documents, Mr. Gellman, a 2002 Pulitzer Prize winner, describes an Iraq that very much wanted to possess the weapons the United States feared it already had. But it couldn’t, for several reasons. Among them were the effectiveness of the U.N. inspections, which demolished most of Iraq’s unconventional weapons in the early 1990s. The much-derided embargo of Iraq also apparently was an important factor in reducing access to funding, weaponry and technical information. On the question of whether Iraq had a missile capable of delivering unconventional weapons long distances, for instance, Mr. Gellman concludes, “Their best estimate was that it would take six years – if the missile worked at all – to reach a successful flight test. [Leading Iraqi rocket scientist Modher Sadeq-Saba] Tamimi would need less time with major help from abroad, but considerably more if he had to conceal the work from U.N. monitoring that persisted until the United States invaded in March.”

In example after example these were Iraq’s calculations – they did not have these weapons but they had plans for them, although sometimes those plans were more fanciful than actual. Part of the reason for this is that the scientists wanted to keep their jobs or advance their careers, so when Saddam Hussein demanded a kind of weapon, the Post story relates, the scientists went to work on it, whether it was possible to construct or not.

In the jargon of analysts, in which red represents the enemy and blue represents friendly forces, this is known as red-on-red deception, and apparently it also fooled the blue. But Mr. Hussein also exaggerated programs or hinted he possessed weapons he did not. Hans Blix, chief of the U.N. inspection team, suggested that the Iraqi leader may have had a good reason for this: “You can put a sign on your door, ‘Beware of Dog,’ without having a dog,” he said.

Instead of weapons of mass destruction, U.S. troops combing Iraq have found mass destruction of the Iraqi people: prisons, torture chambers and graves. The need to rid the world of Saddam Hussein’s influence has shifted from the imminent danger beyond Iraq’s borders to a real danger within them, a devastating problem of long-standing. Mr. Gellman’s work illuminates the most contentious argument for invasion and gives the public a new understanding of this complicated issue.