Andrew Krepinevich, a retired Army officer who wrote the report under a Pentagon contract, concluded that the Army cannot sustain the pace of troop deployments to Iraq long enough to break the back of the insurgency. He also suggested that the Pentagon's decision, announced in December, to begin reducing the force in Iraq this year was driven in part by a realization that the Army was overextended.
As evidence, Krepinevich points to the Army's 2005 recruiting slump, missing its recruiting goal for the first time since 1999, and its decision to offer much bigger enlistment bonuses and other incentives.
"You really begin to wonder just how much stress and strain there is on the Army, how much longer it can continue," he said in an interview. He added that the Army is still a highly effective fighting force and is implementing a plan that will expand the number of combat brigades available for rotations to Iraq and Afghanistan.
The 136-page report represents a more sobering picture of the Army's condition than military officials offer in public. While not released publicly, a copy of the report was provided in response to an Associated Press inquiry.
Illustrating his level of concern about strain on the Army, Krepinevich titled one of his report's chapters, "The Thin Green Line."
He wrote that the Army is "in a race against time" to adjust to the demands of war "or risk 'breaking' the force in the form of a catastrophic decline" in recruitment and re-enlistment.
Col. Lewis Boone, spokesman for Army Forces Command, which is responsible for providing troops to war commanders, said it would be "a very extreme characterization" to call the Army broken. He said his organization has been able to fulfill every request for troops that it has received from field commanders.
The Krepinevich assessment is the latest in the debate over whether the wars in Iraq and Afghanistan have worn out the Army, how the strains can be eased and whether the U.S. military is too burdened to defeat other threats.
Rep. John Murtha, the Pennsylvania Democrat and Vietnam veteran, created a political storm last fall when he called for an early exit from Iraq, arguing the Army was "broken, worn out" and fueling the insurgency by its mere presence. Administration officials have hotly contested that view.
George Joulwan, a retired four-star Army general and former NATO commander, agrees the Army is stretched thin.
"Whether they're broken or not, I think I would say if we don't change the way we're doing business, they're in danger of being fractured and broken, and I would agree with that," Joulwan told CNN last month.
Krepinevich did not conclude that U.S. forces should quit Iraq now, but said it may be possible to reduce troop levels below 100,000 by the end of the year. There now are about 136,000, Pentagon officials said Tuesday.
For an Army of about 500,000 soldiers, not counting the thousands of National Guard and Reserve soldiers now on active duty, the commitment of 100,000 or so to Iraq might not seem an excessive burden. But because the war has lasted longer than expected, the Army has had to regularly rotate fresh units in while maintaining its normal training efforts and reorganizing the force from top to bottom.
Krepinevich's analysis, while consistent with the conclusions of some outside the Bush administration, is in stark contrast with the public statements of Defense Secretary Donald H. Rumsfeld and senior Army officials.
Army Secretary Francis Harvey, for example, opened a Pentagon news conference last week by denying the Army was in trouble. "Today's Army is the most capable, best-trained, best-equipped and most experienced force our nation has fielded in well over a decade," he said, adding that recruiting has picked up.
Rumsfeld has argued that the experience of fighting in Iraq and Afghanistan has made the Army stronger, not weaker.
"The Army is probably as strong and capable as it ever has been in the history of this country," he said in an appearance at the Paul H. Nitze School of Advanced International Studies in Washington on Dec. 5. "They are more experienced, more capable, better equipped than ever before."
Krepinevich said in the interview that he understands why Pentagon officials do not state publicly that they are being forced to reduce troop levels in Iraq because of stress on the Army. "That gives too much encouragement to the enemy," he said, even if a number of signs, such as a recruiting slump, point in that direction.
Krepinevich is executive director of the Center for Strategic and Budgetary Assessments, a nonprofit policy research institute.
He said he concluded that even Army leaders are not sure how much longer they can keep up the unusually high pace of combat tours in Iraq before they trigger an institutional crisis. Some major Army divisions are serving their second yearlong tours in Iraq, and some smaller units have served three times.
Michael O'Hanlon, a military expert at the private Brookings Institution, said in a recent interview that "it's a judgment call" whether the risk of breaking the Army is great enough to warrant expanding its size.
"I say yes. But it's a judgment call, because so far the Army isn't broken," O'Hanlon said.