The U.S. war plan for Iraq calls for 60,000 to 80,000 ground troops to lead the invasion after about 10 days of intensive air strikes to take down air defenses, command and communication centers, and enemy troop concentrations.
Up to 250,000 soldiers, Marines, airmen and sailors will be deployed around the Persian Gulf region. But thousands of ground troops will be held back at bases in Turkey, Kuwait and Qatar as reserve forces in case the initial invasion meets an unexpected resistance, said military sources who discussed war planning on the condition of anonymity.
In a war that most senior Bush administration officials believe will go quickly, the United States will rely more on air transportation of troops than it did in the 1991 war to evict Iraqi troops from Kuwait and push them north toward Baghdad.
In 1991, huge armored and light infantry columns moved north through Iraq and Kuwait by land. In a new attack, many troops would be airlifted inside Iraq from Turkey, Kuwait and Qatar. They would establish operating bases in remote areas and then launch attacks against key Iraqi strongholds.
Key in the attacks will be the performances of stealth aircraft, B-2 bombers, F-117 fighters and Tomahawk cruise missiles. The military will rely on these to take down key command and control facilities and air defenses. Shutting down Iraqi radars and some 60 surface-to-air missile sites will be crucial in allowing a follow-on wave of fighters and bombers to go after Iraq's military, especially dictator Saddam Hussein's most loyal Republican Guard troops in and around Baghdad.
Military officials said the plan calls for avoiding urban combat; casualty rates in street-to-street fighting likely would be high. Instead, the plan is to isolate the capital, spurring Saddam to run. The U.S. hope is that some of his key generals will change sides.
"We're getting a lot of secondhand stuff," said one official when asked whether top officers would fight Saddam.
President Bush and his aides have warned Iraq's generals not to follow orders to use Saddam's arsenal of deadly nerve gas or biological weapons. They also have cautioned the generals not to do anything to harm Iraq's civilian population.
One objective is the early fall of Tikrit, Saddam's political base north of Baghdad. The plan calls for air strikes against all military targets there in hopes the city will fall quickly.
The Washington Times first reported in April that Gen. Tommy Franks, head of U.S. Central Command who would oversee an Iraq invasion, had asked Pentagon officials to approve a total force of more than 200,000.
This touched off a long debate inside the administration. Some Pentagon officials recommended a smaller force, arguing the progress in developing "smart" munitions in the past 10 years allowed for fewer troops.
In the end, Mr. Bush approved the general concept of a plan calling for up to 250,000, the number requested by Gen. Franks. Two sources said Defense Secretary Donald H. Rumsfeld, who had appeared neutral on the issue in internal discussions, sided with his combatant commander.
In what one source describes as a compromise on the total force issue, a significant portion of ground troops will be kept in the region in reserve and may not be needed.
One general theme of the invasion plan is to attack quickly and repeatedly, not giving Saddam's forces time to react.
Mr. Bush said last week: "Should we have to use troops, should it become necessary in order to disarm him, the United States, with friends, will move swiftly with forces to do the job. You don't have to worry about that."
During the air war, and beforehand, the United States will send special operations forces and CIA paramilitary officers into Iraq on reconnaissance missions.
Special-operations commandos also will be responsible for finding and destroying Iraq's stockpile of a dozen or more Scud missiles. Saddam used the ballistic missiles to attack Israel and Saudi Arabia in 1991. With his power at stake this time, analysts say, there is no reason why Saddam would not use chemical or biological warheads in a parting shot at the United States and Israel.
One military officer said he believes the secretive Delta Force, based at Fort Bragg, N.C., has been enlisted to hunt down the Scuds.
Desert Storm commanders failed to locate a single Scud launcher during the 1991 war. The United States later determined that Saddam was hiding the launchers under either ends of bridges. The United States now believes it has improved detection systems that can locate Scud launchers before they fire.
While Mr. Bush has approved the broad outlines of a campaign, many details still must be resolved. "We won't be quick. We will be prudent," Gen. Franks said yesterday.
The Washington Times reported in September that planners were eyeing February as the optimum time to strike and would rely on an unprecedented number of B-2s to kick off the war.
The New York Times and The Washington Post reported over the weekend that the administration had settled on a general war plan.
Gen. Franks is expected to request Army divisions from Europe and the United States, four carrier battle groups, 16 of 21 B-2 stealth bombers and various squadrons of Air Force F-16 and F-15 fighters.
A headquarters element from Central Command, including Gen. Franks, will travel in the coming weeks to Qatar in the Persian Gulf to test a new command center from where an Iraqi invasion could be directed.
A timetable for an attack is event-oriented. If Saddam refuses to allow weapons inspectors inside Iraq, U.S. forces could launch an attack as early as December. The United Nations has given Saddam until Friday to make a decision.
If Saddam complies with the U.N. resolution, an invasion timeline would depend on Iraqi movements to block or deceive the inspection team. A winter campaign would give the military time to win the war and begin rebuilding before the onset of the region's brutally hot spring and summer.
Retired Air Force Lt. Gen. Buster Glosson, who designed the devastating air war against Iraq in 1991, said in an interview that a key first step would be to take away Saddam's network of tunnels under Baghdad. He urged quick air raids and the isolation of key cities as opposed to head-on attacks by ground troops.
"My only nightmare is seeing great numbers of our sons and daughters moving prematurely from Basra and Mosul to Baghdad," Gen. Glosson said in September. "There is no doubt this Roman legion approach to fighting Iraq would also result in victory, but at what cost?"