President Bush faces key decisions in the coming weeks that could signal whether he anticipates a lengthy standoff with Iraq's Saddam Hussein or wants American forces prepared to attack. Among the questions facing Bush: -Whether to add more troops and firepower to the U.S. deployment in the Mideast, now at 220,000 and scheduled to peak at 240,000 in three weeks. -Whether to withdraw some units that are not essential to defending Saudi Arabia, a decision which could serve to assuage growing public concern about the prospects of war without diminishing the force's defensive capabilities. -Approving a Pentagon troop rotation plan, now in the draft stages, that sources said should be ready for White House review in a week or so. -Whether to use his authority to extend 90-day Reserve call-ups for another 90 days. The U.S. deployment reached a symbolic juncture Wednesday with the arrival in Saudi Arabia of the final elements of the 11th Air Defense Brigade from Fort Bliss in Texas. It was the last combat unit scheduled for deployment in the region, Pentagon sources said. The only remaining troops scheduled to be sent to the area are in support units. They should all arrive in the next three weeks, bringing the total deployment to 240,000, said the sources, speaking on the condition of anonymity. ``As of now we're not planning for any additional buildup. We're planning to sustain the force that is present,'' one of the Pentagon sources said. But Gen. Colin Powell, chairman of the Joint Chiefs of Staff, has discussed with ground commanders the possibility of changing the force size. He is due back from Saudi Arabia late Thursday. If Powell recommended, and Bush approved, adding to the force, Pentagon sources said the likely additions would be heavy armor units from the United States, Europe or both. Such orders also would necessitate sending several additional support units into the region as well, the sources said. ``That would ratchet up the pressure on Saddam and give the president the option of surprise if he decided to go on the offensive,'' one of the sources said. ``If a decision has been made to kick him out, then adding to the force first would make it more efficient in terms of loss of life.'' But, barring some development in the crisis that would prompt United Nations support for an offensive, Pentagon sources and military analysts think it far more likely that Bush will tinker with the force - but not dramatically, signaling continued resolve to allow economic sanctions against Iraq to take hold. ``We would have to double the force there to make an offensive palatable from a military standpoint,'' said Lawrence J. Korb, a former assistant defense secretary for manpower in the Reagan administration. ``I don't think that is very likely at all.'' By bringing some non-essential units home, Bush could ``show that we are prepared to stay there for the long haul'' as long as he articulated the reasons for the moves, Korb said. ``Saddam is waiting to see how long we can hold both the support of the American Congress and our U.N. coalition together. I'd set up a rotation plan but basically keep my troop level about where it is.'' If Powell recommends withdrawing forces, the sources said the 82nd Airborne Division, the first ground unit to reach Saudi Arabia, likely would be the first unit brought home. Such a move would not affect the defensive capability of the U.S.-led multinational forces, the sources said. But withdrawing the paratroopers ``would signal that we are going to hunker down and wait right along with Saddam,'' the source said. The withdrawal of even a few thousand troops from the Mideast could also help Bush, whom Korb said ``is obviously not as popular as he was when he started this.'' Said one of the Pentagon sources: ``We'd look good bringing some people home for Christmas, even if in the big scheme of things it didn't amount to much.'' At the same time, ``We have to be very careful about what kind of signal we send because perception is as important as reality in that part of the world and it's easy for things to get confused in translation,'' this Pentagon official said. ``Whether the decision is status quo, reduce or add, the White House is going to have to explain that and ensure that the diplomatic signals that are connected with the decisions are properly read by Saddam Hussein.'' The Pentagon sources said draft rotation plans call for six-month rotations for most units, which would mean the first large-scale substitutions beginning in February. Some units that are harder to replace ``may have to spend more time in country than we or they would like,'' one of the sources said. The sequence of the rotations is still under discussion, this source said. ``We know the soldiers and families are waiting with bated breath but there are some very complicated questions to be resolved.'' When heavy armor units are rotated, the Pentagon would have to decide whether to leave tanks and other equipment in Saudi Arabia or bring them home with the troops. Current thinking is to bring the equipment home, a huge logistical headache, because otherwise the troops would be unable to train at their bases for possible return to Saudi Arabia. Overall cutbacks in the military further complicate rotation planning. For example, the Army alone has to plan for 1.1 million moves in the next 12 months in a force numbering just over 700,000.