CAMP AL-SAYLIYAH: A massive rotation of troops in and out of Iraq, due to be completed in five months, will leave the US military with a far smaller presence there , fewer troops with prior experience in the Middle East and a far greater proportion of reservists in the region.

The US Central Command set in motion this month what will be one of the largest troop and equipment movements in American history. If all goes according to plan, 130,000 troops will fly or drive out of Iraq and 105,000 replacements will move in - all at a time when fighting remains volatile and intense. The military is also beginning to rotate troops in Afghanistan and Kuwait.

The replacement force will have many more units drawn from the National Guard and Army Reserve. Currently, about 28,000 troops in Iraq are from the those groups. After the rotation is concluded in late May, the proportion of reservists will more than double, with 66,000 active-duty troops and 39,000 from the Guard and Reserve.

"I don't think we've had that amount of forces moving in that time frame that I'm aware of, ever," even during World War II, a senior official at Central Command's regional headquarters here said.

The heavier reliance on reservists is a concern in part because those troops had more morale problems than their active- duty counterparts. A survey of 500 soldiers serving in Iraq conducted last month by Charles Moskos, a Northwestern University sociologist specializing in military issues, found that the mood of troops from the Guard and Reserve was "markedly lower."

In a preliminary report to the Army, Moskos noted, "The complaint that reservists were 'second-class citizens' in OIF (Operation Iraqi Freedom) was frequently heard."

The shift poses considerable risk for a military battling an unpredictable enemy that has proved adept at taking advantage of US vulnerabilities. "Anytime you have a large number of forces moving, there's obviously an opportunity for somebody who wants to do something bad," the official said.

Conscious of that risk, commanders have ordered Predator unmanned reconnaissance aircraft to monitor crucial convoy routes. The troop movements are being coordinated with military intelligence on the insurgents' tactics. "We don't do anything operationally without links" to intelligence, the official said.

Once the new troops are in place, a major issue for commanders will be ensuring that know-how is passed from one soldier to the next. Plans call for each incoming unit to arrive about two weeks before the departure of the one it is replacing, allowing the old units and new ones to live and operate side by side.-Dawn/The LAT-WP News Service (c) The Washington Post.