President Bush's decision to send a huge armed force to the Persian Gulf reflects a military philosophy that seeks overwhelming firepower to guarantee victory if war becomes necessary against Iraq, according to administration officials.

This doctrine of invincible force has been the main military principle underlying Operation Desert Shield for the past four months and was at the core of Bush's reasoning when he ordered the near-doubling of U.S. forces in the gulf Nov. 8. "The president has told us not to give him another Vietnam," a top official said last week.

But the drive for military certainty has created controversy in the Pentagon, where the November announcement came as a surprise to many military officers who have been worried about the enormous strains it is placing on the uniformed services.

Beyond the sheer magnitude of the new buildup of an additional 200,000 troops and the further logistical headaches this involves, the suspension of rotation plans -- which would have used the fresh troops to relieve some of those already in the gulf -- was the most startling revelation to most officers.

"That shivered the timbers of the whole military system," one admiral said last week. "It was a helluva signal" of the Bush administration's willingness to marshal as much military firepower as necessary to prevail in the gulf.

Bush may yet order another wave of reinforcements beyond the 400,000 U.S. troops already committed to the gulf, Defense Department officials said.

The guiding doctrine behind the American deployment in the gulf has antecedents that can be traced through a thousand years of warfare; but it firmly took root as the prevailing U.S. approach to combat last December during the American invasion of Panama. That action, code-named Operation Just Cause, stressed secrecy, the figurative "decapitation" of the enemy leadership and the crushing shock of combat power intended to be so formidable as to prove invincible.

After Operation Just Cause, a senior Pentagon official said Friday, those principles were elevated to "a catechism." The doctrine represents a reaction to and rejection of the gradualism of Vietnam and the tentative approach of Desert One, the disastrous and undermanned effort in 1980 to rescue U.S. hostages in Iran.

Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, is the new doctrine's intellectual godfather, and Defense Secretary Richard B. Cheney its political champion. But Bush, who Friday pledged "this will not be a protracted, drawn-out war," has become their most ardent convert.

"If there must be war, we will not permit our troops to have their hands tied behind their backs," Bush said. "If one American soldier has to go into battle, that soldier will have enough force behind him to win and then get out as soon as possible. . . . I will never, ever agree to a halfway effort."

"The president belongs to what I call the 'don't screw around school of military strategy,' " Cheney said in a little-noticed speech in California on Sept. 12. The administration wants to be "absolutely certain" U.S. forces can prevail in combat, Cheney added, and "it would be morally irresponsible for us to send out men and women into battle without every advantage we can give them." To do otherwise, Cheney has said privately, would be "a sin." 'The Engine Driving the Train'

Besides Powell, Cheney and Bush, two other critical policy-makers in the administration are adherents of the doctrine of overwhelming force: Secretary of State James A. Baker III and national security adviser Brent Scowcroft. Officials have said, however, that Baker sees the deployment of a large force as a buttress to diplomatic efforts to avoid armed conflict.

"There are five men who believe in their heads and hearts that the remedy is to present maximum firepower," one senior administration official said last week. "The critics can debate the impact of the {economic} sanctions or the diplomacy or the timeliness of the U.N. resolutions, but that maximization is the engine driving the train. Period."

Though the Cheney-Powell philosophy -- "Jesuits would call it a dogma," one Pentagon official said Friday -- has provided a rationale for the size and shape of the gulf buildup, it also carries hazards that have caused confusion and alarm in the U.S. military. The United States now is in a high-stakes confrontation with Iraqi President Saddam Hussein, who has his own "don't screw around school of military strategy" and has raised his ante to 450,000 troops in greater Kuwait.

Officials said that the United States does not have enough forces in its active duty military to allow for some relief or rotation for those assigned or slated to be assigned to the Persian Gulf theater. Operation Desert Shield also has taxed the military's logistical prowess to an unprecedented degree. Given these pressures, some members of Congress and some military officers warn that the doctrine of overwhelming force may push Bush to "use or lose" his desert army before all diplomatic efforts are exhausted.

Finally, several officers said the Defense Department leadership and Bush may be reaching for certainty where certainty cannot be found.

Articulating the view, retired Adm. William J. Crowe, former chairman of the Joint Chiefs, warned Wednesday: "War is not neat, it's not tidy. And once you resort to it, it's a mess." Echoing this, one senior military officer said last week: "War is a really bad business that defeats any hopeful expectations."

Nonetheless, the Bush administration has sought an insurance policy against the uncertainties of combat by mobilizing a large force from the start. By mid-October, the first wave of troops sent to the gulf had provided sufficient strength to give military officials confidence that Saudi Arabia could be defended from an Iraqi attack, which was the immediate concern after Iraq seized Kuwait Aug. 2.

U.S. military planners had also been contemplating what kind of offensive force would be needed to dislodge the invader. The U.S. Central Command's Operations Plan 90-1002, used as the initial blueprint for Operation Desert Shield and the defense of Saudi Arabia, contained an outline for U.S. offensive operations as well.

But the contingency planning was complicated by the steady, almost exponential growth of the Iraqi occupation. One U.S. intelligence estimate in August calculated that Saddam could muster 18 divisions to defend his prize, according to a Pentagon source; instead, exactly four months after the invasion, Iraq has 28 divisions in the Kuwait "theater of operations," which extends from the Persian Gulf across much of southern Iraq. "The Iraqis generated a lot more force than we thought they could," one U.S. officer conceded last week. Services Focused on Troop Rotation

That force mushroomed from 100,000 in Kuwait on Aug. 2 to 430,000 in the theater on Sept. 25. Saddam also ordered massive armor and artillery forces south, so that by late October Iraq had 3,500 tanks and 1,700 artillery pieces in the theater, with more on the way. Simultaneously, the Iraqis began a prodigious fortification effort, digging ever deeper and laying minefields, barbed wire, tank traps and more than 500 miles of military roads.

By early October, with much of the first wave of U.S. forces either in the gulf region or on the way, U.S. tacticians had completed contingency planning for a second wave, which could provide the critical mass necessary to shift from defense to offense. The plan, which became the basis for the massive reinforcement Bush announced Nov. 8, envisioned a virtual doubling of the U.S. force in the gulf, including an additional 150,000 Army troops.

But within the four U.S. services, planning focused largely on a rotation schedule to begin replacing troops. For example, Gen. Alfred M. Gray Jr., the Marine Corps commandant, ordered his generals to begin drafting a rotation plan on Sept. 18; senior Marine planners met at Quantico, Va., Oct. 10-12, and on Oct. 20, Gray approved a plan that would have replaced the 31,000 Marines in theater with a similar force beginning in February. Comparable plans from the other services began landing on Powell's desk.

In late October, Powell also received a top secret list of options drafted by the Joint Staff. In essence, the list offered four possibilities: keep the status quo to defend Saudi Arabia; tighten the embargo and rely on sanctions to force Saddam out of Kuwait; go to war; or up the ante by moving enough additional forces to the gulf to provide a credible offensive threat.

Powell listened to the presentation of the list without indicating his preference. He also was told that economic sanctions probably would not have any real impact on the Iraqi military for at least six more months and possibly longer.

On Sunday, Oct. 21, Powell left for Saudi Arabia and extensive talks with Gen. H. Norman Schwarzkopf, the commander in chief of the Central Command responsbile for the forces in the gulf region. Schwarzkopf had asked repeatedly for more troops. Among other issues, the two generals discussed the configuration of a reinforcement package if Bush indicated that he wanted to send a second wave of troops.

Schwarzkopf had vowed that if war broke out, he would "guaran-damn-tee it" that the United States would prevail. He and Powell, both four-star generals, discussed "what it would take to have a decisive force," according to a senior Pentagon official.

Although Schwarzkopf and Powell talk frequently by telephone, sometimes several times a day, the chairman's visit to Saudi Arabia also allowed him to hear from Schwarzkopf's staff regarding logistics, intelligence and personnel. During 10 hours of talks, the generals also discussed factors affecting the timing of a U.S. attack -- including religious holidays, weather and the time needed to deploy additional forces -- and concluded that, ideally, the best time for an offensive was the first two months of 1991.

As Powell was leaving Washington, Cheney was returning. On Monday, Oct. 22, he flew back after a trip to the Soviet Union and Western Europe. Asked by a reporter on the plane whether the U.S. buildup was near an end, Cheney replied, "I want to talk to Colin. . . . He's out talking to Norm {Schwarzkopf} and will have a better feel for things when he gets back."

On Wednesday, Oct. 24, Cheney had his usual Wednesday morning breakfast meeting with Baker and Scowcroft. Shortly after noon, he was summoned back to the White House where Bush was giving renewed consideration to the possibility of adding more forces for an offensive capability. No Hints on Hill of New Deployment

Why Bush ultimately decided to press ahead with a reinforcement plan is unclear, although he is known to have been upset by the Saudi defense minister's suggestion earlier in the week of a possible deal with Iraq, including territorial concessions. "I am more determined than ever to see that this invading dictator get out of Kuwait with no compromise of any kind whatsoever," Bush told a political rally in New Hampshire on Oct. 23.

Moreover, the time-consuming and politically damaging budget impasse between Congress and the White House ended on Oct. 24 when Democrats agreed to compromise with Bush.

After his meeting with the president, Cheney went to Capitol Hill to brief legislators on the gulf crisis in S-407, the secure Senate room used for classified meetings. Cheney talked about command-and-control issues and other matters without hinting that discussions were underway for a new deployment of troops to the gulf, according to Senate sources familiar with the meeting.

The next morning, however, Cheney appeared on four successive network talk shows and was willing to signal Bush's new thinking. In taping the "Today" show at 6:30 a.m., Cheney said, "We are not at the point yet where we want to stop adding forces." Asked in his final appearance, on "CBS This Morning," whether he was "getting ready to send another 100,000 troops to the Persian Gulf," Cheney replied, "It's conceivable that we'll end up with that big of an increase. . . . " He added, "We've never set an upper ceiling on" the deployment, a point he repeatedly made in public since the first week of the crisis in August.

The statements surprised not only the members of Congress who had listened to Cheney just a few hours before, but also the most senior U.S. generals and admirals, including Powell and Schwarzkopf, who were "not expecting anything," according to one source.

Powell returned home from Saudi Arabia, after stops in Europe, around 11 p.m. Thursday night, Oct. 25. Cheney left the next day for a fishing trip with Baker in Wyoming. Given the president's desires, the Joint Chiefs began considering how to convert the contingency plan for offensive action into a Phase II deployment plan. As has been his custom, Bush left the details of military matters to the Pentagon; the size and shape of the second wave was up to the generals and admirals.

Over the next several days, Powell went to the Pentagon "and went deep into the bowels of the operations center, into some rooms where not many people are allowed to go, where the real hard-core planning goes on," one source said last week.

Finding the 200,000 or so additional troops Schwarzkopf thought he needed for an offensive was not easy. "It's always a hard decision when you do something like this," one senior official said last week, "but I always go back to the question: What's the objective?" The political objective set by the president, he added, "is to eject the Iraqi army from Kuwait."

The consequent military task would be to fulfill that objective quickly and with minimal casualties, which meant massive firepower. Powell's thinking on the subject, one senior officer said Friday, can be thought of as "Weinberger plus." As the one-time military assistant to former defense secretary Caspar W. Weinberger, Powell has been influenced by a 1984 speech entitled "The Uses of Military Power," in which Weinberger laid out his criteria for deploying forces into combat.

"If we decide it is necessary to put combat troops into a given situation," Weinberger declared, "we should do so wholeheartedly, and with the clear intention of winning." He stopped short of declaring that overwhelming force should be used to guarantee success in battle, a refinement that characterizes the Cheney-Powell doctrine.

As Powell reviewed the forces to be assembled for an offensive punch, they appeared formidable indeed: three aircraft carriers and their escorts plus enough Air Force jets to provide Schwarzkopf with what would amount to an additional 300 planes; a huge armor force including tens of thousands of troops drawn from Europe; thousands of combat reservists; and a virtual doubling of Marine Corps strength in the gulf.

By Tuesday, Oct. 30, most pieces of the puzzle had been pulled together in what some planners began to call Phase II. That morning, Powell and Cheney went to the White House to brief the president on the size and shape of the second wave. The next day, according to two sources, Bush formally approved the deployment, but directed that the decision be kept secret until after the election Nov. 6. President's Stunning Surprise

And secret it remained. Some of the military's most senior officers, including some senior deputies to Powell and Schwarzkopf, continued to work on a rotation plan. As the first week of November passed, a few officers began to hear scuttlebutt that something big was about to happen. Two or three days before the president's announcement, a senior Marine general said last week, he began to hear that the Joint Chiefs were considering a reinforcement plan.

But for most of the military, Bush's declaration on Nov. 8 was a stunning surprise. "I have today," Bush said, "directed the secretary of defense to increase the size of U.S. forces committed to Desert Shield to ensure that the coalition has an adequate offensive military option should that be necessary to achieve our common goal."

In the subsequent three weeks, the Joint Chiefs and services have labored to fully convert their rotation forces into reinforcements. In the Pentagon, civilians and military officers talk increasingly of the coming war.

Staff researchers William F. Powers Jr. and Lucy Shackelford contributed to this report.