An article Sunday stated that Defense Secretary Caspar W. Weinberger has served longer than any other defense secretary except Robert S. McNamara. Charles E. Wilson served from January 1953 until October 1957, about eight months longer than Weinberger has served.

He has become almost a fixture on Capitol Hill during the last month, stepping quickly from office to office with his shoulders slightly hunched, his face startlingly pale against his black hair, his head bowed to receive a whispered instruction from an aide or general as he pursues his blitz on Congress.

For Caspar W. Weinberger, who has been defense secretary longer than anyone except Robert S. McNamara, this is a historic year. The greatest peacetime military buildup in U.S. history is under attack as never before, and Weinberger, its architect and protector, has risen to its defense -- and his own -- with relish.

"The final pledge, the real commitment, must be made by the American people: that we will see our defense program through to its completion and that we will seize the matchless opportunities glittering before us," he said in a speech last week. "That decision must be made this year, in this budget. History will not give us a second chance." But, while Weinberger tirelessly defends the 13 percent military spending increase that President Reagan will request from Congress Monday, his critics charge that he has squandered his own "matchless opportunity" to reform the Defense Department while the budget was on the rise.

The secretary has been attacked every year for "intransigence" on the budget issue. This year the attacks are at a higher pitch. His critics say the defense budget is jeopardizing the fiscal health of the nation, the political future of the Republican Party and -- by allowing the services to buy almost anything they want -- the military health of his department.

"Weinberger reigns but does not rule," Robert W. Komer, undersecretary of defense in the Carter administration, said. "He has devoted the bulk of his attention to getting money out of a reluctant Congress -- and relatively little attention to what the money ought to be spent on . . . He's been, not a bad manager, but a nonmanager."

"He has done a good job in carrying the weight for the administration requests," said Rep. Joseph P. Addabbo (D-N.Y.), chairman of the House Appropriations subcommittee on defense. "But he started by almost completely annihilating civilian oversight of the military services, and because of that we've seen the $7,000 coffeepots, the selling off of valuable surplus property . . . . He disappointed us by not being Cap the Knife."

Weinberger declined to be interviewed for this article, but in the past he has dismissed critics of his weapons procurement record as never having supported a strong defense anyway. He has cited his numerous management initiatives, blamed the $7,000 coffeepots on his predecessors and suggested that, if he appeared generous to the services, it was because they were so needy when he took office.

"Since becoming secretary of defense, I have constantly set improving the management of the department as one of my highest priorities," he told his top aides in a memo last week. Where the 'Savings' Were -

Even Weinberger's critics agree that he has excelled, as President Reagan's point man, at increasing the Pentagon budget.

"I've got to admit that his tactics on how to get money out of the Congress have been very successful," Komer said. "Stonewall to the bitter end and then compromise reluctantly."

Last month, for example, Weinberger announced with fanfare that he had trimmed his $322 billion budget request by almost $9 billion. Most of the "savings" came from revising inflation and fuel estimates that had been set too high, but Weinberger said $2.5 billion would come from unspecified programs.

Officials now say that much of that $2.5 billion came from a $4.2 billion account labeled "legislative contingencies."

Almost no one in Washington -- not even Weinberger, according to those who have spoken with him -- believes that Reagan's $313.7 billion budget authority request for fiscal 1986 will be approved. With a ferocity unmatched in the last four years, Congress has been vowing to whack back the defense budget.

Sen. Mark O. Hatfield (R-Ore.), chairman of the Appropriations Committee, called Weinberger "a draft dodger in the war on the federal deficit." Sen. Charles E. Grassley (R-Iowa) said that Weinberger "ought to recognize that this business-as-usual stuff can no longer work."

Senate Majority Leader Robert J. Dole (R-Kan.) said that "unless we do more on the defense side, we aren't going to do much on Medicare, Medicaid or anything else."

Sen. John Glenn (D-Ohio) and House Majority Leader James C. Wright Jr. (D-Tex.) criticized Weinberger for saying, through a spokesman, that those who want to cut the military budget really want to "weaken the security of the country."

"He shouldn't have said it," Wright said. "It is far too reminiscent of the McCarthy era."

Sen. John Heinz (R-Pa.), chairman of the National Republican Senatorial Committee, said, "I hope Cap Weinberger and Ronald Reagan understand that we are going to need some give on their part to protect the Republicans in 1986," when 22 of the 34 Senate seats up for grabs will be Republican. The deficit will almost surely be an issue and continued Republican control of the Senate could be at stake.

"I've seen a lot of administrations come and go, and I've never seen the Congress act like this, with various committees trying to draw up their own budgets before they've even seen the president's," Michael I. Burch, Weinberger's spokesman and a mirror of his frustration, said last week.

"Others say [privately], 'I'm for a strong defense, I want to help you,' and naturally they're interested in programs in their own states," Burch said. "But you don't see anybody speaking out for a strong defense. They seem to be afraid to speak out."

Even Weinberger's supposed colleagues seemed to be ganging up on him. Donald T. Regan, the president's treasury secretary-turned-White House chief of staff, suggested several weeks ago that defense should not be untouchable. And, while Reagan let Weinberger take the heat in Congress, the president's Office of Management and Budget helped Dole shape an alternative plan.

Weinberger responded with a flurry of press interviews, television appearances and wooing sessions on Capitol Hill.

On Wednesday, for example, Weinberger ate breakfast with 30 Republican members of Congress in the Statesmen's Chowder and Marching Society. He then visited Sen. J. James Exon (D-Neb.) and, after meeting with Reagan and Israeli Defense Minister Yitzhak Rabin, joined the president for a session with members of the House Appropriations Committee.

The defense secretary returned to Congress to call on Sens. Gary Hart (D-Colo.), J. Bennett Johnston (D-La.) and Alfonse M. D'Amato (R-N.Y.) in their offices before traveling back up Pennsylvania Avenue to present some awards and speak to the White House Outreach Group on Central America. Then it was back to Capitol Hill for meetings with Reps. Bill Nichols (D-Ala.) and Charles E. Bennett (D-Fla.) and Sen. Lowell P. Weicker Jr. (R-Conn.).

Finally, Weinberger, who is almost ubiquitous on the Washington party scene (People magazine lauded him as one of Washington's busiest celebrities), attended a cocktail party and the Congressional Dinner, where he was one television network's guest for cocktails and another's for dinner, a spokesman said.

"I don't know how anybody could like going to two or three events a night," Burch said. "He doesn't eat or drink. He doesn't stay to party. He goes to see friends, to make acquaintances. He feels it's important to do as much as he can."

In private and public, Weinberger makes the same arguments: that projected military budget growth has been reduced, that the Soviet Union will not negotiate seriously if Congress kills major weapons, that a compromise with Senate Republicans would only encourage House Democrats to cut more, that if Congress wants to cut it must be prepared to abandon some commitments and that the defense budget is driven by "the Soviet threat," not the U.S. economy.

"That may sound trite," Burch said of the final argument, "but I think people forget it. The people he was talking to today, a group of House Republicans, were writing it down as though they'd never heard it."

Weinberger's consistency year after year is driven by conviction, aides say, and a zest for the role of embattled defender. The more everyone turns on him, they say, the more he seems to enjoy himself.

"In this town, dumb and stubborn is a dangerous combination," a friend of his once said. "But smart and stubborn, which Cap is, can be a very powerful combination."

His certainty also is based on confidence in Reagan's support. In 1981, when Reagan's closest aides gleefully announced defense budget cuts, Weinberger calmly reminded reporters that they had not heard from the only man who counted. When the president finally spoke up, Weinberger had won.

Audits Question Spending -

It may have been inevitable that Weinberger's remarkable success in winning budget increases would spark criticism that he was letting the military services run wild. Certainly, his record of internal management, which Congress is likely to examine closely as it considers the budget request, is less clear than his record as chief Pentagon fund-raiser.

A series of recently released audits by the Defense Department inspector general showed the services spending millions of dollars on weapons that Weinberger had not yet judged to be affordable or necessary.

His top aides, including Richard D. DeLauer, who recently retired as undersecretary for research and engineering, complain to friends that they rarely see Weinberger except in large staff meetings. Those meetings, aides say, are devoted less to substance than to discussions of how Defense Department programs are playing in the press and Congress.

Weinberger's comptroller, normally the official who cracks the whip on service budget requests, is respected but untried Robert W. Helm, who has little management experience. The deputy secretary, traditionally an industrialist who takes charge of day-to-day management, is Weinberger's longtime aide and confidant, William Howard Taft IV, also with little management experience.

"Will is smart and I admire him," said one old hand in the Pentagon. "But I think it displays a notable lack of understanding about what the problems are when Cap appoints his protege, a 39-year-old attorney, as Mr. Inside."

When his more aggressive aides have taken the initiative to cut costs, Weinberger has not appeared to stand in their way. But when other aides did not follow suit, Weinberger has not appeared to push them in the same direction.

Thus, Navy Secretary John F. Lehman Jr. appointed a competition advocate in 1983 and the percentage of sole-source Navy contracts has declined steadily. But the Air Force and Army did not follow suit until Congress ordered them to, and their proportion of competitively let contracts has changed much less.

Rep. Les Aspin (D-Wis.), chairman of the House Armed Services Committee, announced last week that his panel will examine whether Weinberger has bought $1 trillion in defense with the $1 trillion Congress approved during the last four years.

"They kind of scrambled around, took some programs off the shelf and blew the dust off them and asked the services to tell them what they wanted," Aspin suspects.

"Power has been decentralized to the services, and the most money has gone to the noisiest," Komer said. "Throwing all this money at them has led to greater waste and sloppy practices."

Burch disagreed, saying that Weinberger has "gotten tough with the services to get tough with contractors." He said that the secretary meets every two weeks with managers of major programs and that he had involved the Joint Chiefs of Staff and theater commanders in the budget process more than before.

Above all, Burch said, Weinberger has tried to restore what he and Reagan view as adequate funding. "How is the man being intransigent?" Burch asked. "He takes an oath . . . and now he's carrying out the responsibilities of the office."