by Thomas E. Ricks
  
Despite the rapid advance of Army and Marine forces across Iraq over the past week, some senior U.S. military officers are now convinced that the war is likely to last months and will require considerably more combat power than is now on hand there and in Kuwait, senior defense officials said yesterday.

The combination of wretched weather, long and insecure supply lines, and an enemy that has refused to be supine in the face of American military might has led to a broad reassessment by some top generals of U.S. military expectations and timelines. Some of them see even the potential threat of a drawn-out fight that sucks in more and more U.S. forces. Both on the battlefield in Iraq and in Pentagon conference rooms, military commanders were talking yesterday about a longer, harder war than had been expected just a week ago, the officials said.

"Tell me how this ends," one senior officer said yesterday.

While some top planners favor continuing to press north, many Army commanders believe that the pause in Army ground operations that began yesterday is critical. A relatively small force is stretched thin over 300 miles, and much of the Army's killing power, in more than 100 AH-64 Apache attack helicopters, has been grounded by persistently foul weather or by battle damage from an unsuccessful pre-dawn raid on Monday. To the east, the Marine Corps advance on the city of Kut was also hampered by skirmishing along its supply line and fuel shortages at the front.

More forces are coming, including the Army's 4th Infantry Division, which has begun pushing equipment from 35 ships into Kuwait after Turkey refused to allow U.S. forces to use its bases for a second front, into northern Iraq. But it will probably take the better part of a month for that tank-heavy division to get into position and provide combat power. Other forces heading to this region, including the 3rd Armored Cavalry Regiment, based at Fort Carson, Colo., and the 1st Cavalry Division, from Fort Hood, Tex., will require months to move their tanks and other armor from their bases into combat, the defense officials said.

Pentagon spokesmen rejected that pessimistic assessment yesterday and insisted that the war is still going according to plan. "The plan has moved almost exactly with expectations," Army Maj. Gen. Stanley McChrystal said at the briefing. "Fast where we expected it to be fast, gathering strength where we expected to do that. So the answer is, it's right on the mark."

But Secretary of State Colin L. Powell, a former chairman of the Joint Chiefs of Staff who maintains close ties to some senior Army generals, seemed to break with part of that assessment, saying in an interview with National Public Radio yesterday that it was becoming evident that the war "may take a little bit longer, don't know how long." He added: "The point is we have had a good battle plan, and it's a battle plan that will succeed."

In the short term, the Army plans to secure its strained supply lines with a portion of the 82nd Airborne Division, now positioned near Kuwait City, and troops from the 101st Airborne Division, which is gathering at a forward operating base deep inside Iraq, Army sources said.

The degree to which the supply lines have been stretched can be seen in the fact that the 3rd Division this week was alarmingly low on water and was also in danger of running short of food, the sources said. Heroic efforts have been made by truck companies and other logisticians, but a certain amount of chaos has developed, exacerbated by sniping and immense traffic backlogs from the Kuwaiti border. That traffic jam also has undermined Bush administration plans to quickly follow the U.S. military advance with tons of food and other humanitarian relief to win support among Iraqis.

"There's tremendous fog out there," an officer said, referring to the confusion of wartime operations, with logistical commanders struggling to figure out where various supply items are in a system that at times resembles "just a bunch of guys out there driving around."

Commanders would like to have a 10-day supply of food, water, ammunition, fuel and other basic supplies before launching a concerted offensive, but equally critical are items such as batteries and vehicle parts.

Also, Army commanders have differing views about how vigorously the war must be prosecuted in Iraqi cities and towns. "How bad do you want to do it? We have the capability to surround a city, cut off the water, cut off the electricity. We don't want to do that," said one general. "It's all about having military success, not about attacking the civilian population. But you have to break [Hussein's] will, to make him understand that he will not win."

But another officer noted that rooting out militiamen and other irregulars fighting in southern Iraqi cities would enormously complicate the U.S. military effort, requiring more troops and many more supplies. "Let's say you throttle An Najaf," he said. "Then you've got 600,000 people in the city and surrounding region you're responsible for providing food, water and medical care for." Each additional combat unit sent to Iraq also will add to the logistical strain, he said.

Overhanging all developments in the war this week is the unsettling realization that thousands of Iraqis are willing to fight vigorously. During planning for the invasion, worst-case scenarios sometimes predicated stiff resistance, but "no one took that very seriously," an officer said.

"The whole linchpin of this operation was the reaction of the Iraqi people and the Iraqi ground force," said retired Army Col. Robert Killebrew, a specialist in war planning. "If they don't turn, and so far they haven't, we have a very different strategic problem facing us than when we went in."

When Army combat operations resume, major adjustments are likely in strategic goals and targets. The sources said that some of the major assumptions underpinning the U.S. approach are being discarded. The planned blitzkrieg to Baghdad has stalled. Air power has delivered less than expected. And Saddam Hussein and those around him still appear to have a firm grip on the Iraqi military and people. In an extremely unusual battlefield action, two Army M1 Abrams tanks were badly damaged in combat Tuesday.

An Army general and others said that rather than slice through Republican Guard defenders and drive straight for Baghdad, the Army and Marines are likely to be forced to focus on wiping out most of the Guard divisions facing them south of Baghdad.

"I think you need to defeat them in detail," said the general, using the military term for destroying a unit. "I think you should 'Pac Man' the ring around Baghdad," he said, referring to the 1980s computer game in which a big dot gobbled up smaller ones.

Retired Gen. Barry R. McCaffrey said the Army and Marine forces converging on the Republican Guard south of Baghdad will have no choice but to continue to attack those Iraqi defenders. "We've got no option, we're committed," he said. But, he added, "I wouldn't go into Baghdad before I had another armored division come up into my rear."

The question is whether the 3rd Infantry Division will be able to continue to fight the Republican Guard without reinforcements. "I think the Third I.D. is going to run out of steam pretty soon, both people and machines," said Killebrew, the retired Army planner.

But McCaffrey, who during the 1991 Persian Gulf War commanded what is now the 3rd Infantry Division, said he thought the unit was capable of taking on all three Republican Guard divisions on the southern side of the so-called red zone that marks the capital's defensive perimeter.

Another key variable is how effective U.S. warplanes will be in aiding the Army and Marines by hitting Iraqi military forces in the heavily populated, well-vegetated Euphrates River valley. That is a far different proposition than striking Iraqi armor in the flat, open desert, which was the major task of U.S. air power in the Gulf War. Over the last two days, U.S. airstrikes have been curtailed by the powerful sandstorms that have howled through central Iraq.

Military intelligence indicated that elements of the Medina Division of the Republican Guard were taking advantage of the cover provided by the tail end of the storms to move toward the Karbala Gap, a narrow strait between Lake Razzaza and the Euphrates, a military official said yesterday.

Some Pentagon officials were practically gleeful at the development, with one saying the column would be "like shooting fish in a barrel" or like "a turkey shoot."

But others were less sanguine. The column is moving from fighting position to fighting position, from revetment to revetment, always taking protective cover. "This is their turf," one official said. "They've probably done exercises there their whole life. The defense of Baghdad is all they've trained for."

Finally, the resilience of the Medina Division will be a major indicator of whether the 3rd Infantry Division can do the job by itself or will have to dig in and wait for help in April from the 4th Infantry Division.

Unless the Iraqi government collapses after part of the Republican Guard is destroyed, an attack on the capital is likely to be postponed until that division arrives, some defense officials and other experts predicted.

"We're not going to rush headlong into the city, absolutely fruitless to do so and suicidal at best," a Pentagon official said. "The goal is to encircle the city and take it on our terms."

Retired Army Col. Benjamin W. Covington, an expert in tank warfare, agreed, saying: "Everything on the ground depends on the arrival of the 4th Infantry Division. I expect the final battle for Baghdad will occur when they are in the fray."

Some Pentagon insiders and defense experts vigorously contested these pessimistic assessments.

"This is not a crisis," said former House speaker Newt Gingrich (R-Ga.), who is a friend of Defense Secretary Donald H. Rumsfeld and of Army Gen. Tommy R. Franks, the U.S. commander in the war. "The plan is going surprisingly well so far."

Gingrich, who also is a member of the Defense Policy Board, a top Pentagon advisory group, said the key fact to keep in mind is that U.S. forces drove to within 50 miles of the capital in just six days without being engaged by regular Iraqi forces. "If they come out and fight us, they will be annihilated," he said.

Retired Army Lt. Col. Andrew Krepinevich agreed with Gingrich's view, saying: "Despite the best efforts of the Iraqi military, they have not been able to stop a fantastic rate of advance, one of the greatest advances in military history, and they have not been able to do more than ding the coalition juggernaut."

One senior general at the Pentagon, listening to both sides of the argument, said he thinks that in short term the pessimists will look right, but will be proved wrong by mid-April. "There are some tough days ahead," he said. "I think this whole thing is at the culminating point. Within the next week to 10 days, we will find out about the mettle of the Republican Guard." But he concluded, "Once we smash the Medina and Baghdad divisions, it's game over, and I think Baghdad will fall."

Correspondent Rick Atkinson in central Iraq and staff reporters Jonathan Weisman and Vernon Loeb in Washington contributed to this report.

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