Every Friday morning at 8, a dozen or so high-level Senate Democratic staff aides meet for breakfast in room S-120 of the Capitol to exchange ideas and talk over the legislative outlook.

The breakfasters are known to few people off Capitol-Hill. Their names are seldom in the papers. Sometimes they eat bagels, sometimes they eat grits. They don't always agree with each other. They seldom make formal decisions.

But, taken as a group, they form the top stratum of an invisible network of staff power and influence in the Senate, with impact on the life of every citizen of the United States.

At any one breakfast you might find Mike Pertachuk, chief counsel and staff director of the Senate Commerce Committee (one of the most respected but also controversial staff chiefs); Frank Sullivan of the Armed Services Committee; Jim Callaway of Appropriations; Bill Simpson, a key aide to Sen. James O. Eastland (D-Miss); Mike Stern of the Finance Committee, or Democratic Policy Committee staffers like Tom Hart or Lee Williams.

Elected by no one, responsible only to their chairman or to the leadership, well paid (most get $41,750 a year), the staff directors of the Senate committees have enormous power over the laws and programs that govern the nation. Without doing anything corrupt or immoral, they can exercise a lot of influence on the way legislation comes out.The same is true for top assistants who work in the offices of individual senators.

And as an added psychological bonus, they are courted by lobbist and can indulge a certain imperiousness. Leon Billings, chief aide to Chairman Edmund S. Muskie (D-Maine) of the Environmental Pollution Subcommittee, was heard telling his secretary a few days ago, "Tell Ford [Motor Co.] we want them to testify. No is not an answer. We want a witness."

So powerful are top staffers that it sometimes appears they rather than senators are running the institution.

"The reason for all this," Sen. Robert P. Griffin (R-Mich.) said, "is that senators have so much to do, so many assignments, they leave too much to the staff." One senator, for example, Charles H. Percy (R-Ill.), has had 28 committee and subcommittee assignments. He can't possibly keep track of all the work himself.

Sen. Dick Clark (D-Iowa), a former staff man in the House before he ran for the Senate, concurred: "Dependency on staff is great. Domination, no. Dependency, definitely. There is no question of our enormous dependency and their influence. In all legislation, they're the ones that lay out the options."

Clark had just returned from a Senate ethics committee meeting and he gave this illustration: "The staff spent 10 hours drawing up an outline for a proposed code of ethics. Then we spent two hours studying it. We worked hard on it - but they drew up the options."

Some time back, Clark unwillingly gave an excellent example of dependency of staff when a reporter asked him for an explanation of a complicated amendment he had just offered. He made an attempt to explain, then, scratching his head, said jokingly, "Let me ask my brain." He turned to a staff aide behind him who had worked out the actual language. The aide provided a full explanation.

A staff director to a major Senate committee (who asked not be identified) explained the ways, in which it is possible to influence the work of a committee.

"It's hard, but it can be done. It's easier with a weak chairman, but I happen to have a strong one. I look on myself as his eyes and ears. I look for issues he's interested in. We think all alike on a lot of issues. But the point is, I'm the eyes and ears.

"Usually, you draw up proposals for the year's agenda, lay out the alternatives. You can put in some stuff you like and leave out some you don't. I recommend ideas that he's interested in and also that I'm interested in.

"You [and lower staffs] write the position papers. You give recommendations to the senator on how to handle things. You brief the [other] members on an issue, and your point of view comes through there. "If you're in favor of something you make sure the best witnesses for it are there. Of course, aides to senators with a different point of view will make sure to get their witnessess there, too."

This staff director and several others said that simply slipping a provision into a bill that the committee hasn't approved can't be done successfully anymore. "Too many people review the legislation, and they find it.'

"The staff doesn't run the Senate, but members do rely too much on staff for information. They ought to trim their assignments and do more of the actual intellectual work themselves. These guys are so busy, so stretched out, they rely on staff for judgements on how to vote, what legislation to back - if they get burned, they get rid of that staff guy and get another they can rely on."

The "eyes and ears" function means listening to lobbyist, reading all the literature on a subject, pushing ideas forward to the senator. It also means writing his speeches and advising him how to vote.

An illustration of how it can work occured a few years ago, when Cary Parker, a top aide to Sen. Edward M. Kennedy (D-Mass.), was reading through some literature on the 18 year-olds vote, which at that time was not allowed. He discovered to his delight that two top legal scholars, Archibald Cox and Paul Freund of Havard law school, had come to the conclusion that Congress could give the vote to 18-year-olds in federal elections merely by passing law, rather than by constitutional amendment, as had always been thought necessary.

Kennedy had always been interested in the subject, and Parker excitedly took the materials to Kennedy and worked up an amendment to tack onto the Voting Rights Act Extension bill. Civil rights groups begged Kennedy not to do it, for fear voting rights extensions might be endangered. He hesitated, but then-Majority Leader Mike Mansfield (D-Mont.) didn't. He introduced the amendment for himself, Kennedy and Warren G. Magnuson (D-Wash.), and rammed it through Congress - and that's how the 18-year-olds got the vote.

Sometimes staffers are caught overeaching themselves and get slapped down.

Carl Macry, a highly respected former staff chief on Senate Foreing Relations, had to offer to resign because of GOP anger after he allowed language critical of President Nixon's Cambodia bombing order to remain in a report (written by another staffer) where it wasn't relevant. He was immediately rehired, but the report was withdrawn and repeated without the extra language.

Harley Dirks, longtime aide to Magnuson on the Appropriations Labor Health, Education and Welfare Subcommittee, was ousted after he published a document making it appear that a hearing on a certain subject had taken place, when in fact it hadn't. The published document had senators and witnesses making statements to each other.

Staff members deal with lobbysist all the time, getting their views, running ideas by them and, sometimes, getting a friendly lobby to put pressure on some issue may be undecided. During close votes, the Senate public lobbyist conferring on which senator the lobbyist should "hit" next.

Billings, chief aide to Muskie on the Enviornmental Pollution Subcommittee, which handles autoand other Pollutants, said, "We'll meet anybody who wants to talk.Since Jan. 24, I've talked to Peter Keppler of Amex (coal, aluminium); technical people from Chrysler and General Motors; Herbert L. Hisch, Ford vice president for engineering; the Environmental Protection Agency; the Association of State Water Pollution Control Boards," and many others.

Billings says that once Muskie decides on a position, it's his job to sell it and he doesn't hesitate to talk to staff of other senators, hold briefings for them ("We try to show them that the bill is good"), and "If I hear of someone who ought to be for us but is against us, I might call his aide and say, "Do you have a problem that I can help you with?" I even suggest from time to time that Muskie talk to individual members.

"But anyone who says that I run the subcommittee grossly underestimates Ed Muskie. No one transcends the member. Staff people who do that get cut pretty quickly."

Right now there is a changing of the guard. Some of the longtime powerhouse among the staff are gone.

Marcy ("the ambassador," some jokingly called him), who headed the staff of the Foreign Relations Committee under J. W. Fulbright (D-Ark) has retired. He helped as much as any senator to foster an anti-Vietnam war consensus onthe committee, which he fanned by his brilliant handling of the press (leaks, story ideas, etc).

Ed Braswell, Sen. John C. Stennis' (D-Miss.) hardworking top aide on Armed Services, has also retired. Larry Woodworth, head of a huge joint committee staff that handled tax bills in both the House and the Senate, is assistant secretary of the Treasury for tax policy now.

Woodworth was so highly respected that when Congress decided to look into President Nixon's tax situation, it handled Woodworth and his staff the problem and let them come up with judgements that, in effect, cost Nixon over $400,000 in back taxes. Charles Harris, chief domestic adviser to Mansfield for over a decade, has switched to counsel to House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) now that Mansfield has retired. Frank Valeo, Mansfield's foreign policy adviser and secretary of theSenate, will soon retire.

An informal survey of Senate insiders. asked to name the most unfluential staffers at present, unhesitatingly, named Mike Pertschuk, Magnuson's top aide on the Commerce Committee, as No. 1. Jim Callaway, chief aide to Appropriations Committee Chairman John L. McClellan (D-Ark.), was a close second. Staffers on Appropriations say it's clear McClellan has great confidence in Callaway's judgement, and when the senator needs advice on matters like the weapons budget or anything else he will turn primarily to him.

Ken McLean, staff director on the Banking Committee, is another who is rated very high. So are Billings and Dick Wegman of Governmental Affairs. Jerome Levinson, director of Sen. Frank Church's (D-Idaho) Multi national Subcommittee, is described as having done a brilliant job looking into the CIA-ITT linkin Chile and corporate bribes to foreign officials.

Two other officials with considerable influence are William Hildenbrand, secretary of the GOP minority, and J.S. Kimmitt, soon to be secretary of the Senate - both oldtimers with plenty of knowledge of how things are done and willing to share it with all the senators for whom they work. Hildnebrand has long been known as the man with the best votecount in the Senate.

Pertschuk is undoubtedly the most controversial staff man in the Senate now because some Republicans think Magnuson "let him run wild."

Said oneGOP member of the Commerce Committee: "Sometimes it seems he's really running the committee. He doesn't do anything illegitimate. He's doing what Maggie wants, but he shouldn't have so much leeway."

What Pertschuk is accused of is being too ardent a consumer advocate, of "lobbying" members of the committee on behalf of things he thinks are good, of putting his own philosophical "spin" on options, of having excessive influence on Magnuson; in short of acting like the "101st senator."

He denies in, and he has some convincing defenders. Ted Stevens (R-Alaska), a member of the committee, laughed uproariously when asked if he considered Pertschuk to dominate Magnuson. "He's a good staff man. I've known Maggie for a lot of years, and I don't think anyone runs Maggie."

Sen. Ernest F. Hollings (D-S.C.), also on the committee, called Perschuk "outstanding. He's assembled the has best team of experts on natural gas, oceans, consumerism, everything the committee does. He does what Sen. Magnuson wants him to do. The Republicans know that. He's been ahead" in his understanding of issues.

Pertschuk, with strong backing form Magnuson, is in line for the Federal Trade Commission. Whether his expected successor, Ed Merlis, will have the same excellent chemistry with Magnuson remains to be seen.

Pertschuk, 44, came to the committee in 1964 as its consumer counsel and became its staff chief, for all practical purposes, in 1968. "I dominate the chairman? Absolutely untrue. He determined what the limits of my job are."

"I carry a daily list of decisions to clear with him," he said, fishing such a list from his pocket."Before I do anything, I get his okay."

Pertschuk freely acknowledge he talks to Nader; to Joan Claybrook, the head of Nader's Congress Watch; to United Auto Workers lobbyist Dick Warden; the AFL-CIO lobbyist, Ken Young; to International Ladies Garment Workers Union lobbyist Evelyn Dubrow - but he said he also consults frequently with people like Bryce Harlow, adviser to Republican presidents and longtime lobbyists for Procter & Gamble; Grocery Manufacturers Association chief George Koch, and Aaeron Yohallem of the Chamber of Commerce.

He says he first presented the idea of no-fault auto insurance to Magnuson after reading of it in an article by Daniel Patrick Moynihan a decade ago, and that he got the idea for the Consumer Product Safety Commission and agency from hearings on auto safety, which led him to wonder about other products.

All these suggestions have led to committee action.

The most common view around the Senate is that staff has tremendous power to influence senators in the ways described above, but seldom actually dominates a senator.

"I don't see any staff guy emerging as the 101st senator, that's a crock," said one of te savviest oldtime staff men. "A lot of that is a myth. A staff guy can have only as much influence and power as he's allowed to from his leader."

Levinson, asserting that Church reviewed in advance every proposed step of the multinational investigation, said a staff man who short circuits his boss or beging to think of himself as a senator has limited his legislative life.

"If the staff runs away and goes beyond what the chairman understands has been agreed on, you can kiss the investigation goodbye. And you can kiss the staffgoodbye."