DHAHRAN, Saudi Arabia -- Iraq's highly touted military defenses withered so quickly once the allied ground offensive began that U.S. tanks charged into Iraq 10 hours ahead of schedule while thousands of astonished American soldiers never had to fire a shot.
During the first day of the assault, a U.S. Army howitzer team rolling into Iraq ahead of the 82nd Airborne Division and French forces encountered a barrage of artillery fire that landed 100 yards ahead in its path.
After firing back for half an hour, the artillerymen learned that what appeared to be Iraqi shelling was merely covering fire from U.S. guns stationed to the rear. Iraqi troops actually had fled their forward positions, with one soldier leaving behind a plate of cold rice and an onion.
One of the 82nd Airborne brigades had expected a violent clash with as many as 2,500 seasoned Iraqi soldiers, but at least 2,000 Iraqis ended up surrendering, almost every one of them without firing a round.
Had they wanted to fight, the Iraqis were equipped with heavily stocked and well-fortified bunkers to put up stiff resistance, Col. Ron Rokosz, the U.S. brigade commander, told reporters traveling with the unit.
"It's the most incredible thing I've ever seen," he said. "Every soldier I saw surrendered."
From across the 300-mile battle front, stretching westward from the Kuwaiti coastline to the Iraqi desert well beyond the Wadi al-Batin basin, U.S. and allied forces broke through minefields, 12-foot sand barriers and other obstacles with ease. Allied armor units then churned through much of the desert with unexpected speed.
Since the all-out offensive began early Sunday, U.S. commanders have been quick to attribute much of the initial success to the battle plan drafted by senior Army officers, which stressed rapid, flexible maneuvering to exploit Iraqi weaknesses several fronts and the use of deception.
In one case, the entire Army VII Corps began on Feb. 14 to shift westward across the Wadi al-Batin to take up positions close to a jump-off point near the spot where the border turns northward.
As the long convoy and tanks and vehicles moved more than 100 miles west, the 1st Cavalry Division began shelling Iraqi troops repeatedly from positions closer to the Kuwaiti border, apparently convincing them that the main U.S. thrust would come at that point.
When the VII Corps launched its attack, Iraqi resistance was virtually non-existent, allowing commanders to move their armored divisions north 10 hours ahead of schedule.
"We had to totally revise the ground plan," said Col. Johnnie B. Hitt, corps aviation commander. "There was enemy right over the border, but they were not fighting."
Yesterday, when asked why allied forces could advance so quickly into Kuwait and Iraq, Marine Brig. Gen. Richard I. Neal said, "I think it was superb prior planning, if you want the truth."
Maj. Gen. Ronald H. Griffith, commander of the 1st Armored Division, put it this way: "We have speed, we have agility, we have shock-attack firepower, and he [Iraqi troops] can't do that."
New reports from the combat zone also indicate that Iraq largely abandoned its traditional Soviet-style battlefield tactics and simply chose, in many encounters with allied forces, not to fight.
Although bunkers have been found full of ammunition and supplies -- even one with a military radio, a color television and a VCR -- the will to fight clearly had been lost.
Some advancing Marines reported pockets of heavy artillery fire as they broke through the defensive lines, but others in the 1st Marine Division saw no resistance at the first layer of obstacles, only sporadic opposition at the second layer and then moved rapidly to their first objective: seizure of a former Kuwaiti air force base.
This unit discovered that Iraqi fortifications were impressive only because of the extent to which they covered a vast landscape, not so much for the way they were built. Some defensive positions were little more than shallow trenches or bunkers made with flimsy materials.
The first barriers 10 miles inside Kuwait, for example, consisted of two lines of single-strand barbed wire on either side of a minefield. The mines were half-exposed. The Iraqis had almost no troops or artillery covering the obstacles, even though advancing U.S. Marines did not have tanks and were vulnerable.
At the next obstacle belt, another eight miles or so into Kuwait, the Marines took light artillery fire, but it was ineffective.
"They had a dynamic opportunity because we were all bunched up," said Cpl. Mark Thieme of Alexandria, Va. "But they didn't take advantage of it."
Elsewhere across the battlefield, the threat by Iraq's much-vaunted fleet of 190 attack helicopters failed to materialize. Not only were its pilots -- like those in Iraq's moribund air force -- judged too timid to fight, but U.S. field commanders also disclosed that helicopter airstrips were bombarded heavily only a few hours before the allied offensive began.
In addition, U.S. Army helicopter gunships and scouts roamed 50 miles into the desert of central Iraq to deal with potential resistance while leading columns of allied armor and ground troops.
"Some guys had said if this is your day off, you're going to miss half the war," said Capt. Gordon Spencer, an F-16 pilot from North Syracuse, N.Y., who had flown tank-busting missions Sunday to clear the way for the ground forces.
After plowing through all the Iraqi obstacles and reaching his first objective, a jubilant member of the 1st Marine Division exclaimed, "Damn, if I knew it was going to be this easy, I would have said come earlier."