THE NATIONAL SECURITY high command has been summoned in special session, midway through Ronald Reagan's California summer vacation, so the president can hear what his advisers believe will be Caspar Weinberger's recommendations on how to cut some $30 billion from the huge increases in the defense budget.

Budget Director David Stockman, with James Baker giving him inside support, delivers a preamble for what the White House advisers think is the consensus that has been worked out in advance. He begins by making the familiar case that the cuts are essential to a strong economy -- and a strong economy is essential to America's defense.

Weinberger is sitting there with his eyes closed in a tight squint, pinching the bridge of his nose with his fingers; it is a trademark gesture that is sometimes taken for annoyance or pain, but is really just concentration.

Now Weinberger speaks. He too has shown up with support: a phalanx of generals and admirals and graphic charts of warfare. He is advocating no cuts at all.

"Without a strong defense," says Weinberger, "a strong economy has no meaning."

And the man whom Washington once knew as the budget-cutter at OMB and the secretary of HEW adds: "If we go to war, it won't be fought with social services."

Across the table, his friend Ronald Reagan seems to be nodding his assent. The administration is embarking on a big-spending course that will plunge it into controversy for months to come. Republican eagles of industry will dissent, and even Republican hawks in Congress will fire off their press releases of protest. The Reagan Revolution will fall into civil war.

"Cap is probably the least flexible man on the team. Cap sets a path and simply does not get off of it. At times, we don't know if Al (Haig) is on it or off it."

-- A senior White House official.

"Cap is like this: Once he gets an idea into his head, he won't let go. He'll debate you by just repeating, and repeating, and repeating, until he wears you down. . . . Don't transfer western technology to the Soviets; don't build a Soviet pipeline to Europe; call Poland's debt. It's all total war with Cap."

-- A senior Pentagon official.

Inflexibility: it is key to the understanding of Caspar Weinberger and his performance as the president's secretary of defense. He is at first glance an enigmatic sort: a soft-spoken and courtly Renaissance man who speaks only of hardline anticommunism; an Anglophile whose comments lock him in combat with the allies of Europe; an ambitious man with a zest for diplomatic mission but no taste for diplomatic nuance; an Episcopalian who has a Jewish surname, Arabist instincts and a special fondness for Saudi Arabia.

But those who now work alongside him and against him, and those who have known him in each of his past incarnations, know him most of all as a man who is ruled by his own rigidity.

"I've always been accused of being too rigid," Caspar Weinberger concedes. He is sitting in his office -- E Ring, 3rd Floor, that large, institutionally spare chamber where one of his first orders was that the portraits, done in Pentagon Traditional, be replaced with "Titian and Assistant, 1590."

As he explains his renowned singlemindedness of purpose and pursuit, he talks of himself in the first person plural:

"Once we take a position, why, we don't waver around. Because we spent a lot of time coming to that position, and analyzed most of the arguments and don't come to the position lightly or easily. But once, once it's done . . . and if you're satisfied that the position is one that is necessary and effective, why, changing rapidly, usually it produces very inferior, ineffective programs."

Inflexibility: it is the steely thread that binds each of the episodes of Caspar Weinberger's reign as secretary of defense.

It accounts for the early weaponry decisions that that have been rigidly defended rather than modified, even, in the case of the MX missile, at the price of forcing the Reagan administration into unnecessary embarrassment.

It explains the public comments, unfettered by diplomatic concern, that have triggered tremors overseas.

And it undergirds the private counsel of virulent anti-Sovietism that shapes his every contribution inside the Reagan administration and the NATO alliance.

Within the meetings of the Reagan administration, and within the only occasionally more cacophonous meetings of the NATO alliance, Weinberger has frequently cited the example of Winston Churchill to buttress his fortress arguments. "Cap is a Churchillian scholar," says one senior Defense official who is very much a Weinberger admirer. "I think he sees himself as a latter-day Churchill trying to rearm the West."

Weinberger concurs.

"He is one of my great heroes," he says. "He warned that Europe must rearm against the threat from the Germans and he was right -- and they barely did it in time. He was the only one warning it at that time -- it was considered bad form and he made something of a nuisance of himself. Now I am trying to emphasize the fact that I see some rather deadly parallels. The threat is from the Soviets, and we must rearm."

To those who would charge that Weinberger entered the Pentagon ill-prepared for the job he faced, Weinberger offers a quick reply:

Right.

"I think the fair way to phrase it is that I came in here not really having sufficient knowledge to make judgments on many of these matters."

That, Caspar Weinberger goes on to say in his refreshingly candid and forthright way, did not stop him from making those early judgments that set him on the course he has pursued at full throttle ever since.

He brought to the Pentagon years of government experience, but all of it domestic: as a state legislator; as a director of a state budget for California's Gov. Reagan, and of a federal budget for Richard Nixon; as a chairman of the Federal Trade Commission under Nixon; and as a secretary of health, education and welfare under Nixon and Gerald Ford.

"I didn't really come in with any preconceptions at all -- most people will tell you that I didn't come in here with enough concepts! I had the tabula rasa, I guess, which is considered either very desirable or dangerous -- one or the other. Anyway, we came in and . . . we had to move very rapidly, because we had a 1981 budget that was moving and we had a 1982 budget that was submitted, and we had serious problems with both of them. And we had to do a very full-scale revision of both budgets in a very short time, and we also had a lot of other things that had to be done. We had to staff the department, . . . innumerable meetings across the river and all the rest.

"So that, as is always the case, there wasn't time to do the thing properly . . . We just tried to do everything at once."

"It was a cram course?" he is asked.

"Oh yes, yes, more than that," Weinberger replies. "A survival course!"

The military services, like the snow machines on mid-Atlantic ski slopes, dutifully cranked out a blizzard of paper for the new defense secretary, burying him with rationales for mountainsized purchases of new hardware. Meanwhile, atop the ever-precarious slopes of Capitol Hill, Senate Armed Services Committee Chairman John Tower (R- Tex.) furnished the guidance that Weinberger must move quickly and grandly, before the cheers of the election mandate could be drowned out by the clamor of lesser believers.

This was Weinberger's initiation by avalanche. Jimmy Carter had bequeathed to his successor a 1982 budget of $196 billion. The military services were asking Weinberger to boost it to $206, according to a senior defense official. Weinberger wound up asking for $222 billion -- more than the Joint Chiefs were asking. And in the process, "Cap the Knife" (as in cutting) became "Cap the Saber" (as in rattling).

While the widely publicized intramural battle of the budget (Stockman, Baker et al vs. Weinberger) would not take place until late in the summer and fall of 1981, in fact Weinberger's initial decisions had already launched the administration on its big spending course.

Many of the key decisions were made in those first weeks: the construction of the B1 bomber, the expansion of the Navy from 400 to 600 ships and the building of two new, huge aircraft carriers. Moreover, Weinberger was pressing to put all of this new hardware in place on rapid construction timetables, ignoring advice from a number of prominent fellow conservatives and hawks that the production and purchases could be slowed to reduce the deficits in the years ahead.

Weinberger is asked about the process by which he made his quick decisions: Would he do it all the same way, once again?

"Wellll, ideally, no. . . . But we were not granted that luxury."

Had he been granted the luxury of time -- or, more to the point, if he had insisted upon taking enough time to adequately study defense needs before his first spending decisions -- would he have made the same decisions? Where would his budget have ended up?

"I don't really know. I haven't any idea. Maybe exactly where I did. It's very hard to say. We did find a situation in which -- to my considerable astonishment -- we were worse off than I thought we were, and we needed almost everything. There was quite literally nothing that we did not need. And this led some people to say that we were simply picking up money and hurling it at the problem, and that we were indiscriminate. Well, we were not. We still did try and I think did sort out some priorities within a very short time."

Military requirements, it turns out, were only part of Cap Weinberger's computations.

"Our first strategy was to get well . . . to get the armed forces in some kind of condition that they could deal with whatever crisis might arise. Secondly, it was vital to change the perception of the United States in the world, and that perception was very bad -- very unreliable ally, no willingness to fight, no willingness to stay with a tough course.

"A lot of very vague perceptions that all we were really interested in was human rights and what is generally viewed as the equivalent of unilateral disarmament. A lot of pious hopes and hand-wringing but no willingness to insert any muscle into the process. And a whole raft of perceptions about the country that weren't all that wrong, unfortunately, but had urgently to be changed . . ."

How important was a new, high level of military spending to this goal of changing the world's perception of the United States?

"Very important. Rightly or wrongly, it's the index by which the resolution and the will of America is judged. And in this case, because it meant the acquisition of things we urgently needed, and doing it at a time of economic difficulty when we were reducing all of the other departments, practically speaking, . . . All of these things at the same time conveyed to the world a picture of a total change in the United States and an astonishing dedication to the idea of regaining strength in the face of what all of the people interested in normal politics would tell you was an impossible set of conditions."

February 1981: Defense Secretary Caspar W. Weinberger declared yesterday that he favors deploying neutron warheads in Europe . . .

(Weinberger's press conference comment, just two weeks after taking office, created waves of controversy throughout Europe, prompting the State Department to cable NATO capitals that his remarks did not constitute a change in U.S. policy against deploying the weapon in Europe.)

September 1981: Defense Secretary Caspar W. Weinberger, commenting on U.S. allegations that the Soviet Union may be using chemical-biological warfare in Cambodia, indicated yesterday that the United States might revise treaties banning such warfare or develop an ability to "respond in kind" as a deterrent to Moscow.

(Weinberger's comments on a Voice of America brattle ooadcast caused considerable unrest within the State Department. In an unusual step, the broadcast was aired along with an official clarification that U.S. policy on biological warfare "is very clear" and that the U.S. has renounced any use of such weapons in "full compliance" with the international convention.)

A low, late afternoon sun is filtering through the windows of the office, E Ring, 3rd Floor, casting a shadow across "Titian and Assistant, 1590."

An interview that had begun at 2 p.m. is now threatening to go past 6. This is not to say it has been one long-playing dialogue. Weinberger has excused himself to take a call from West Germany -- only to return a minute later to explain somewhat sheepishly that the Pentagon's phone line had somehow gotten disconnected. He has adjourned three times to take calls on another special, secure phone line from the president's new national security adviser, William Clark, and he has taken leave to attend a meeting with the Joint Chiefs which was supposed to last 30 minutes but lasted almost an hour and a half.

He has returned on each occasion apologizing profusely for keeping his guest waiting, and then he has submitted, with unfailing good grace, to further inquisition.

He is asked, for example, about his frequent public comments, which prompted frequent public clarifications, and gave rise to a private nickname: "Ready! Fire! Aim!" (It is a trait he shares with his boss, the president; thanks to the two of them, the clarification business is booming into Washington's strongest recession-era cottage industry.)

Consider Example Number One. Weinberger's early comment on the need to deploy neutron weapons produced shock waves and protests in Europe. Does he believe he handled the matter properly? And would he handle it that way again?

"The neutron weapon was talked about a good bit during the campaign. There should not have been any doubt in anybody's mind that the cancellation of the neutron weapon by Carter, after he had persuaded some of the Europeans to accept it, was something that we criticized very heavily . . .

"It just seems to me that if you repeat at a press conference or you repeat before Congress things that you have said before that are part of the campaign, part of the platform, part of the policy as it is known, that it is a little surprising that there should be such an outcry as if you had announced some totally new policy."

Weinberger is off and running on a favorite theme -- about how he has been consistent in word, thought and deed throughout the maelstrom that has been created by those around him. He is, of course, right when he says that he has long favored the neutron bomb, and so has his boss. But he seems unaware of the diplomatic repercussions that such a pronouncement by a senior policymaker would surely ignite. Others around him were well aware. ("I almost fell off my chair when Cap said that," says one senior defense official.)

Midway through his discourse on the propriety of all that he had said, Weinberger suddenly stops and -- sensing that his response is being found unconvincing -- asks a question of his own.

Weinberger: "Give me your reaction. You obviously are puzzled by these answers."

Reporter: "No, not puzzled. I understand what you are saying. . . . Although I would say that you would have been wise at the same time to understand from your lessons in government in the past about defense secretaries and secretaries of state and presidents: When they say something, it's a policy."

Weinberger ponders, then acquiesces.

"I think that's fair enough," he says. "I'm frank to tell you that I did not realize the importance that would be attached to each statement that is made. And that is largely because nobody gave much of a hoot what I said when I was at OMB or HEW."

Those were not completely hootless days for Weinberger, when he was running the OMB for Richard Nixon, because when Cap the Knife spoke then, a whole Cabinet listened -- and at times some of them answle oered back.

Among them, Melvin Laird. Then secretary of defense, Laird has recalled that Weinberger opposed his plans to build the B1 bomber at the time, and, favoring a slower approach, convinced Nixon to take the funds for the B1 out of the budget. Laird got his way then only by dispatching Deputy Defense Secretary David Packard, the multimillionaire California defense contrctor, to meet with Nixon and threaten to resign at once if the B1 were not reinstated. Nixon changed his mind and overruled Weinberger.

Weinberger is well aware of Laird's recollection. It is somewhat a sore point with Weinberger -- so much so that he brings it up even when he is not specifically asked about it.

"Mel was always under the impression that I fought the B1 and didn't put the money in. He's told me that 100 times, and I've set him straight 100 times. The simple fact is that we wanted it in a little different form than he did. . . . We had disagreements about which year we would start certain things . . . But Mel's feeling was that if he didn't get what he asked for within the first five minutes, it was an unsuccessful meeting. But we ultimately ended up with essentially the programs the president wanted."

Those who were at the Pentagon during Weinberger's OMB years find it hard to reconcile the analytical, cost-conscious man they faced then with the man who runs things from the E Ring, 3rd Floor today. Recalls one former top defense official: "Cap was for the low figure on everything."

At the Pentagon, Weinberger has become known instead for staking out his positions early, and then fashioning a rationale to fit the conclusion.

There are, according to a senior White House adviser, at least two decisions that Weinberger pressed upon the president that Reagan now wishes had been given further, and fresher, thought: the MX missile and the neutron weapon.

Despite the diplomatic furor provoked by his early comments about neutron warheads, and his own fondness for things European, Weinberger remained naive about European sensitivities to the program. An act of Congress had directed that components for the neutron missiles and artillery shells be produced and stored in the United States, but not assembled to make them usable. But Weinberger pressed Reagan to order that the neutron weapons be assembled and stockpiled in the United States for quick deployment in Europe.

Reagan issued the order -- and it touched off the predictable demonstrations and protestations in Western Europe, including criticism from such circles as West German Chancellor Helmut Schmidt's own Social Democratic Party. Weinberger proudly hailed the decision in a press conference, saying that now the weapons could be delivered to troops in Europe in "only a few hours." And Weinberger went on to compound his diplomatic felony by callously dismissing the European opposition as "largely a tribute to the effectiveness of the Soviet propaganda campaign against this weapon."

At the White House, Weinberger's initiative and response are now seen as having created unnecessary international problems. Says one senior presidential adviser:

"Everyone but Al (Haig) underestimated the European reaction. Cap pushed pretty hard for what he argued was not a momentous decision: just assemble the weapons but do not deploy them in Europe. But Al predicted that any stirring would precipitate strong emotions in Western Europe.

"Had we been sure of the effect of our action in advance, it would have been done differently. And we sure wouldn't have sent Cap out on three press conferences Monday morning to glorify it!"

The MX missile decision provoked problems of another sort.

All through the 1980 campaign, Ronald Reagan was warning of a "window of vulnerability" through which the United States was vulnerable to Soviet nuclear attack. He vowed, if elected, to close that window.

For years, out of concern about the vulnerability of U.S. land-based missiles, Republican and Democratic administrations had approved work on a missiwle ole that would be mobile -- able to be moved from site to site to make it difficult for the Soviets to target it for first-strike destruction. It was the MX.

The problem then became how to base this new, mobile missile. Carter opted, after much study, for a plan known as the modified racetrack: Each MX missile would be deployed along a large oval track that contained 23 protective shelters, one to house the missile and the rest to serve as decoys. The missile would be secretly rolled from shelter to shelter.

The idea was to force the Russians to play American roulette. America's 200 MX missiles would be concealed somewhere within 4,600 shelters. The Soviets would have to fire most, if not all, of their stockpile of 6,000 hard-target warheads to assure that they could knock out America's MX arsenal.

That was the theory. But in the 1980 campaign, Reagan derided the Rube Goldbergness of it all. Weinberger too had been saying harsh things about the racetrack plan: "It wouldn't be hard for the Soviets to put together enough missiles to bang every hole."

Upon assuming command at the Pentagon, Weinberger quickly made it clear to his subordinates that (1) the new administration intended to deploy the MX; and (2) it was not going to be along Carter's racetrack plan.

He was initially enamored of the idea of de- mothballing old battleships and floating them out into the oceans with MX missiles on board. But his deputy secretary, Frank Carlucci, and others with intelligence experience told him that these old ships would be as easy for the Soviets to target as fixed holes in the ground.

Weinberger commissioned a study from his deputy undersecretary for research and engineering, Seymour Zeiberg. The study concluded that a modified version of the Carter racetrack idea -- a linear grid track -- was the only other way. Weinberger scrapped the study and pressed on. (Zeiberg now works for the Martin Marietta Corp. in Orlando).

Weinberger hoped that the MX missiles could be put on airplanes and kept airborne. But the experts, including those of the Air Force, told him they had no assurance the MX could be fired accurately from an airplane.

Meanwhile, Weinberger convened one of those blue-ribbon panels, the Townes Commission, which reported at length that there was no good solution to report.

It was shortly after this that Weinberger announced that he had found a solution. The MX would be placed in old Titan or Minuteman missile silos, and these silos would be "hardened" to make them less vulnerable to Soviet attack.

This presented one minor problem: The experts, including those in the Air Force, knew that silos cannot be sufficiently hardened to make the missiles inside them invulnerable to Soviet attack. This proposal had originally been presented a decade earlier to then-Secretary Laird, and he had rejected it after the Air Force told him it couldn't work.

But the Air Force experts say they did not have a chance to lay out their case to this defense secretary. They say they repeatedly requested to brief Weinberger on it, and were repeatedly rebuffed. Weinberger, perhaps wary of leaks, made his decision with a minimum of consultation. Air Force Secretary Verne Orr, in fact, was informed of Weinberger's decision shortly after the press was given its first briefing on it.

Weinberger's decision was duly announced as policy by President Reagan, at a press conference in which the president seemed singularly uninformed of the details or rationale of the program he was announcing. Weinberger's decision has brought Reagan nothing but embarrassment ever since.

Importantly, Weinberger's plan did nothing to close that "window of vulnerability." The old missile silos would be as vulnerable as ever. The Senate Armed Services Committee, an aviary of hawks, has unanimously rejected Weinberger's basing system for the MX. It has also refused to vote funds for advanced procurement of the missile.

"Cap is strongly anticommunist. Not much background, not much sophistication. So in looking at foreign policy, he takes a hard, simplistic line: They are the enemy; it is us against them. In his morning meetings, the theme that comes through is, 'These are the bad guys. Don't help them.'"

10 -- A senior defense official.

That explains, among other things, how Weinberger has come to oppose all of Western Europe and most of the State Department in his dogged advocacy of two controversial actions. He is urging that the United States block construction of the Siberian pipeline that would carry gas from the Soviet Union to Western Europe; the project, he says, will generate some $10 billion in hard currency for the Soviets, which they will channel largely into military purchasing.

So, too, he is advocating that the United States force the calling of Poland's debts to the West, to compel the Soviets to bail out the Poles with precious hard currency.

Weinberger explains that he does not want to press these matters to the point of breaking up the Western alliance. But he does think the United States has an obligation -- a leadership obligation -- to carry the fight to the Europeans, even when it promises to be a long, lonely effort.

It is positions like these that have nurtured a sharply drawn philosophical comparison between the secretary of defense and the secretary of state. It is a comparison that finds Haig, the former NATO commander, very much the multinationalist; and Weinberger, at last resort, willing to be an isolationist. And it is a comparison that sets Weinberger off on a softly spoken soliloquy of dissent.

"It infuriates me when I hear that. I spent a large amount of my time losing intraparty arguments (in the name of international cooperation). We could not live in a world if Europe were overrun. I'm trying to strengthen them, strengthen Europe."

He goes on to lay out his multinationalist credentials. His terms, his frame of reference and his reasoning are of the counter-Soviet era of the Cold War.

"I have always felt that . . . one of the most important factors in keeping the peace is the NATO alliance. And I have known that since its inception that has been a cardinal point of the Soviet policy to try to destroy it.

"So I've never wanted to do anything but strengthen the NATO alliance, and I feel that way today. I worry about the opinion in Congress, the rising perception that now that we have started to rearm, a lot of other countries don't seem to be doing as much . . ."

And he launches one last effort to explain his view of the value of multinationalism:

"Because it's exactly what I used to say in World War II -- it's just a great deal easier and more effective to defend California in New Guinea than it is from Oregon."