Officers, active-duty and retired, and analysts predict that war would likely come between the mid-February end of the hajj, the annual Muslim pilgrimage to the holy Saudi Arabian city of Mecca, and early March.
That window will probably remain open at least until Feb. 14 when United Nations weapons inspectors present their next report on Iraqi compliance with disarmament demands to the Security Council.
Longer delays, stretching into the spring, analysts say, could erode voter confidence in both Bush's leadership and the U.S. economy. Such delays could also have an adverse effect on the support of Mideast allies for a U.S.-led invasion and the fighting edge of frontline American troops stationed in Kuwait and neighboring countries and aboard ship.
Tens of thousands of U.S. troops are pouring into the Persian Gulf region, while huge cargo ships are loading tanks and other equipment near the East Coast, Texas and California. Aircraft carriers are steaming to the region, with four expected there by the second week in February, Pentagon officials said.
"I think the main [military] capability will be in place by the third week of February," said William Arkin, a former Army intelligence officer and defense analyst. "If we're not at war by March 15, I'd be stunned."
Loren Thompson, a defense analyst at the Lexington Institute, agreed that with most of the force in the area by that time, "The last week in February would be the most likely time to move."
Retired Army Lt. Col. Ralph Peters, a former military planner, said top commanders would likely be given "a number of dates" or "windows" when they could execute a presidential order to attack.
Peters said bowing to political sensitivities in Europe and the Mideast, a U.S.-led invasion would probably wait until after the hajj, the Muslim pilgrimage.
Some U.S. officials note that with so many charter aircraft and travelers heading to Saudi Arabia, safety concerns might preclude an invasion until a few days after the pilgrimage is over.
In Germany, a weeklong computer simulation that tests plans for a war in Iraq will wrap up next week. The war game, "Victory Scrimmage," includes commanders of several units, such as the Army's 101st Air Assault Division and the 1st Marine Expeditionary Force, that are expected to take part in an attack.
Also, at a military base in southern Hungary, about 100 Iraqi opposition figures who had been living in the United States will begin training next week to work with U.S. forces as translators, guides and military police. Up to several thousand more opposition figures are expected to travel to the Taszar base from Europe and the Middle East for similar training during February, opposition officials said.
Pentagon officials and analysts said the outline of an Iraq invasion plan will combine the speed and airborne attacks of the 1989 Panama invasion with the armored punch of the 1991 Persian Gulf war and the precision bombing of the 2001 Afghanistan campaign.
Plans call for the U.S.-led forces to surge into the country from many directions - Kuwait, Turkey, Jordan and Saudi Arabia - rather than just the southern route from Saudi Arabia taken by U.S. troops in 1991.