After invasion of Iraq, then what?

WASHINGTON - Senior military officers are deeply concerned about the cost, demands and hazards of occupying Iraq, including the teeming capital city of Baghdad, should U.S. forces overthrow Saddam Hussein.

Some estimate that it would take thousands, if not tens of thousands, of troops to patrol Iraq, especially Baghdad, where the prospect of revenge killings, ethnic rivalry, terrorism and a humanitarian crisis could dwarf the urban perils faced by U.S. troops in Somalia in 1993.

Defense Secretary Donald H. Rumsfeld, appearing before Congress last week, declined to publicly discuss the number of peacekeeping troops that might be needed, but a study conducted for the Army based on 16 U.S. military occupations in the 20th century - dating to the Philippines in 1902 - estimates that about 100,000 occupation troops would be required to patrol a post-Hussein Iraq.

Moreover, a former strategist for the Joint Chiefs of Staff, retired Army Col. Scott Feil, predicts that 75,000 U.S. troops would be needed for the first year, with an undetermined number after that.

A force of that size would carry a high price tag. Feil, director of strategy for the Joint Chiefs in 1999-2000, placed it at $16 billion for the first year.

Still, some say the number of troops needed for an occupation - and the associated costs - can only be determined after the fight. Anthony H. Cordesman, an analyst with the Center for Strategic and International Studies, said that suggesting a number beforehand is akin to "predicting the outcome of a slot machine."

"Certainly we should have a significant presence," he said. "We're not going to do that, it's clear, with 500 men."

The prospect of a large occupation force is troubling some members of Congress as they take up a resolution that could grant President Bush sweeping authority to remove Hussein from power and eliminate his weapons of mass destruction.