Guessing about collateral damage.

How many Iraqi civilians will die in Gulf War II? It's one of the most disturbing questions going into this battle—the question that fills doves with passion and hawks with doubt—so a few activists and analysts have tried to develop an answer. The most widely circulated one comes from a confidential report by a U.N. humanitarian-aid specialist, which was leaked to a group in Cambridge, which in turn published it on the Internet. This report estimates that civilian casualties could total 500,000. Another much-cited public study, by the International Physicians for the Prevention of Nuclear War, cites a figure of up to 100,000. If these calculations were even close to plausible, they would certainly strain many of the rationales for going to war, especially those that involve the liberation and welfare of the Iraqi people.

So, it's worth asking: How were these numbers computed? On what assumptions—especially about U.S. strategy, tactics, weapons, and targets—are they based? There's an old phrase among those who work with computer models: "GIGO," for Garbage In/Garbage Out. Feed a computer silly assumptions; it spits out ridiculous numbers. Not to paint a rosy picture on the devastation wrought by any war, especially this one, which is likely to be fought partly in densely populated cities, but these numbers are textbook cases of GIGO. They're not so much wrong as they are completely useless.

The U.N. study, which was written last December (the author has not been revealed, though the document's authenticity has been confirmed), makes the following assumptions about the course of the war:

• That U.S. and allied bombing will severely damage Iraq's electrical power plants, generators, and distribution networks, which will have a grave effect on the country's electrified water and sanitation systems;
• That the port of Umm Qasr will be disabled, thus blocking imports of vital supplies;
• That the country's railroad tracks, bridges, and key roads will be destroyed, disrupting internal travel, trade, and post-war aid.

The International Physicians' report makes the same assumption: "The destruction of roads, railways, houses, hospitals, factories, and sewage plants will create conditions in which the environment is degraded and disease flourishes." These structures and networks were key targets in the 1991 Gulf War; they were bombarded heavily and repeatedly. As a result, according to several independent estimates, about 3,500 Iraqi civilians were killed during the war, and another 110,000 died from the after-effects on the country's health and sanitation system. In a similar vein, the leaked U.N. study calculates that 100,000 civilians will die during the coming war, plus 400,000 after the war.

Here's the fallacy, though: In this war, the United States has no intention of attacking power plants, railways, or bridges—or not many, anyway. Several news stories (for example, click here) have said as much, but logic makes the same point.

First, this time around, the U.S. leadership seems genuinely interested in rebuilding Iraq after the war. It makes no sense, therefore, to bomb these kinds of targets, the repair of which would only make an already-difficult job even more costly and time consuming.

Second, and more pertinent, the basic aims of this war are very different from Operation Desert Storm. In 1991, the goal was to push Iraqi troops out of Kuwait and make sure they couldn't reinvade afterward. Bridges, railways, and roads were bombarded in order to cut off those troops—in Kuwait and in southern Iraq—from command channels and supply lines. Electrical power plants were destroyed in order to "blind" Iraq's politico-military machine. This was necessary to keep Saddam's intelligence officers from detecting the vast movement of U.S. troops and armor just across the border. This movement, which had to remain covert to be effective, allowed the United States to sweep up and around the dug-in Iraqi soldiers, surrounding them from the rear and the flank and thus attacking them from all sides, once the ground war started.

The destruction wreaked by this bombing was horrendous, especially since Bush I bugged out right after a cease-fire was reached, helping neither to rebuild the country nor to overthrow Saddam. The point here, though, is that power plants, bridges, and so forth were considered military targets in 1991; they are not—or at least not remotely to the same extent—in 2003. If these sorts of facilitiesare not bombed much in the coming war, then the assumptions in the U.N. and International Physicians' report are completely off-base, as are the casualty estimates that go with them.

A closer look at those reports' numbers reveals a great deal of looseness, even if their assumptions were pertinent. The U.N. report does not lay out the range of estimates—a failing that, given the range of uncertainties in any war, makes the calculations inherently suspect. (How 100,000 civilians are supposed to die in the course of the war, from the bombing alone, is not explained.) However, the International Physicians' report does lay out a range. In Baghdad, it states, civilian deaths caused directly by the war will total between 2,000 and 50,000; wounded will reach 6,000 to 200,000. In Basra, Diyala, Kirkuk, and Mosul, civilian deaths will be between 1,200 and 35,000; wounded, between 3,600 and 120,000.