WASHINGTON -- The way military historian Trevor Dupuy sees it, the lesson of the gulf war is as ancient as warfare itself.

"The most important lesson is that the fundamental principles of war that were valid at the time of Alexander the Great were as true today as they ever were: mobility, mass and maneuver," Mr. Dupuy said. And because the United States adhered closely to all three, he said, Operation Desert Storm "was probably as close to a flawless operation as has ever been done."

It also didn't hurt to have secret warriors on the prowl behind enemy lines in the desert, unsung robotic simulators that helped train pilots to "Top Gun" sharpness, up-to-the-minute satellite photos of practically every enemy position, warplanes free to roam wherever they wanted and an opposing commander as rigid as the Sphinx.

Among the pleasant surprises were the secret fighting units, also known as Special Operations units, or "special ops." While Americans at home watched the pyrotechnics of the air war beginning over Baghdad, these outfits were parachuting behind enemy lines into Kuwait and Iraq, in places as far off as Kurdistan, then moving by night to their missions in muffled, ultralight dune buggies.

"They were in there from the very beginning," said James F. Dunnigan, a military analyst working on a Persian Gulf war book, From Shield to Storm. "They were up in Kurdistan, they were all over the place. They think they've lost a number [of these soldiers] which they haven't confirmed yet. But that's the rules they play by."

The units "were invaluable for intelligence," he said.

One thing they did was cut the fiber-optic lines that connected Iraqi units to their commanders, he said.

Less likely as a hero, and even more unsung, are the robotic flight simulators found on U.S. bases where pilots are trained. But they played a key role in the air war, which in turn was the key to the ease of coalition success.

"The simulators played a big role," Mr. Dunnigan said.

"You can do things you wouldn't dare do [in a real plane]," Mr. Dunnigan said. "They might say, 'Let's see you bring it in with half the wing gone,' or, 'Let's see you try to take it in at 50 feet off the ground and see if the bombing will work that way.' "

As a result, he said, many planes got back to base that wouldn't have without a pilot who had already "flown" by trial and error in such conditions.

The biggest pleasant surprise of the war was the incredibly low rate of U.S. casualties once the ground fighting started.

And, as military analyst and consultant Harry Summers, of Bowie, said: "From the fact that [commanding Gen. H. Norman Schwarzkopf] stockpiled 60 days of supplies, it was obvious he didn't think it was going to be this easy, either."

But a clue to why victory came so easy might be found in the biggest miscalculation of the war by U.S. military intelligence. Though an estimated 450,000 Iraqi troops were said to be arrayed in the war zone, Army officials now say privately the figure may have been as low as 250,000 by the time the ground offensive began.

Mr. Dunnigan thinks the latter figure is too low, but he agrees that the earlier numbers "just didn't add up. . . . It was probably more like about 300,000."

How did the mistake occur?

Mr. Dunnigan blames two factors. Satellite photos, he said, showed 40 Iraqi "formations," which normally would include about 10,000 troops each, plus others in medical and supply outfits.

"But how many of these units actually got up to strength is hard to say. A lot of guys apparently didn't show up for the train ride south, perhaps to the extent of 30 or 40 percent. It's apparently pretty easy to disappear in Iraq. They're not going to go look after Mohammed the farmer. He can go to his cousin's village and work in the fields for a while."

Also, once the troops were in place, it probably wasn't that hard for some soldiers to desert despite the threat of execution for those who were caught.

But this error, at least, didn't cost any U.S. lives. "It was one case in which I was gloriously happy to have been wrong," Mr. Summers said.

Other surprises included several poor-mouthed weapons systems that performed far better than expected. The M-1A1 tank, for instance, had been decried as a breakdown waiting to happen. Instead, as Mr. Herman said, "They just moved 1,500 of those things across the desert at lightning speed."

But not all the expensive weapons now being touted as successes were tested on the very things that were supposed to be their weaknesses.

The Bradley Fighting Vehicle, for instance, supposedly had trouble in field trials in shooting down air targets unless they were standing still. In the gulf war the Bradleys had virtually no air targets to fire at.

Also, considering the opposition, Mr. Dunnigan argues that even the successes of the M-1A1 (which he praises as "a gonzo weapon") might have been just as easily achieved with less expensive weapons.

High-tech domination on land and in the sky was what helped the coalition forces blind the Iraqi army from the outset by knocking out radar and communications posts. Once that was done, they say, even the best generals couldn't have saved the Iraqi army.

The communications shutdown also contributed to the further decline in Iraqi morale, the analysts say, doubtless adding to the toll of mass surrenders by Iraqi front-line troops during the four days of the ground war.

Once coalition forces began moving into Kuwait and Iraq, the Iraqis had virtually no way of knowing nor any way of passing on word of the attack.

But hidden in the huge achievement of the low-cost victory are a few weak spots.

First, there is the inability of the United States to move its land forces into position rapidly, or, as the military calls it, not enough "rapid sealift" capability.

"The sealift situation is probably one of our greatest weaknesses," Mr. Dupuy said.

Mr. Herman said, "If Saddam Hussein's tanks had been rolling on the way to the oil fields in August, none of those units would have been there other than the 82nd and the 101st, and they still would not have been able to stop a Republican Guard armored thrust. . . . Things like sealift and minesweeping are not glamorous, but they're a poor man's way of getting at you."

There were also ominous signs that the hazards of "friendly fire" have become even greater with the advent of laser-guided weapons. An estimated 23 U.S. troops and nine British soldiers were killed by "friendly fire," which set off a flurry of bureaucratic activity to come up with more than some short-term remedies.

"It's unsolvable," Mr. Dupuy said bluntly.

"It's the ultimate dirty old secret in the military," Mr. Dunnigan said. "It's very common, and of course with all these 'smart' weapons it's going to become a big stink. . . . There's not a hell of a lot you can do about it except discipline the troops, because undisciplined troops will shoot at anything."

As further reports emerge, Mr. Dunnigan expects more shortcomings to surface. Some may even involve blunders in the field. "I'm sure there were some battalion and brigade commanders who in action proved to be less adept than they were thought," he said. "But, again, the National Training Center has weeded most of the total bozos out. So even there you probably won't find real horror stories."