WASHINGTON – Stretched by frequent troop rotations to Iraq and Afghanistan, the Army has become a “thin green line” that could snap unless relief comes soon, according to a study for the Pentagon.

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 sobering picture of the Army’s condition than military officials offer in public.

Although not released publicly, a copy of the report was provided in response to an Associated Press inquiry.