There was a time not so long ago when, to be blunt, it wounldn't have mattered much if newcomers like Marty Russo or Dave Stockman were members of Congress.

They would have come to Washington, scrambled to stay in office, patiently learned the system, listened respectfully to their elders, accrued seniority. Eventually good things would have come to them, as though by divine confirmation: committee or subcommittee chairmanships, clout enough to cow a bureaucrat, even the power to influence national policy.

It is not that way anymore, which is one of the reasons President Carter's proposal to curb skyrocketing hospital costs never found its way through the thicket of the 95th Congress.

Russo and Stockman have spent a total of six years in Congress - not much in an institution known as a haven for septuagenarians. But when the administration's bill was beaten in the House Commerce Committee last summer, it was they - and not powerful committee chairmen or leaders like speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) - who played key roles.

Russo, a two-term Democrat from Chicago's southwest suburbs, broke with his party and Carter - who before he was president had helped elect him in 1974 - to cast the vote that killed the administration cost-control plan.

Stockman, a freshman Republican from Michigan, developed amendments that effectively gutted the majority president's plan and persuaded his colleagues to approve them.

A number of factors, including administration miscalculation and industry lobbying, came together to undermine the hospital bill. But one of the more obvious factors was Congress itself, the way it functions these days and the attitudes that guide it.

Russo and Stockamn, as neophytes with a voice, are beneficiaries of some of the major changes that occurred in Congress during the past decade - changes that dramatically affect the way business is done.

House and Senate changes have spread more power to younger members, giving many of them (including Russo) subcommittee chairmanships. Heavy turnover - more than half of the members have come here since 1972 - keeps the committees changing rapidly.

Chairmen, feaful of ouster, no longer can run their committees as personal duchies, dictating members' votes. This was particularly true on the hospital bill.

Party loyalties are divided and younger members, feeling more independent, respond to their own instincts and special power bases at home.When the Commerce Committee defeated Carter's cost control bill, nine of the 22 votes against it were cast by Democrats. Six of the nine were first or second-termers.

Reforms have created something approaching subcommittee government in Congress, and while these reforms have eliminated some overlapping jurisdictions, Carter's hospital bill had to face four subcommittees. Each had a chairman with a different idea.

On the Senate side, Edward M. Kennedy (D-Mass.) supported the Carter bill. Herman Talmadge (D-Ga.) thought Carter's bill was too sweeping. In the House, Rep. Dan Rostenkowski (D-Ill.) didn't like mandatory controls. Rep. Paul Rogers (D-Fla.) supported the controls, but he knew compromises would have to be made.

Each of the four subcommittees would get to take a crack at Carter's bill. And then each of the four parent committees would have its turn.

This meant more members would be able to tinker,that special interests would have more opportunities to work their will, that the administration's task of getting its bills passed would be infinitely harder.

A decade ago, for example, Carter's bill would have gone to one committee in the House and one in the Senate.Last year, it went to two committees in each chamber and subcommittees in each committee. That made eight major station stops.

The bill reached seven of the eight stations but at each of the stops it ran into peculiar problems of politics, power and personalities.

After the first stop, however, the administration had reason to be buoyed. Kennedy's health subcommittee moved quickly and produced a bill that in several respects was tougher than what Carter had proposed. By early August 1977, the full Human Resources Committee had approved the Kennedy bill. Joseph A. Califano Jr., the secretary of health, education and welfare, cheered it as a "dramatic first step."

At the same time Carter's plan was in Kennedy's Senate subcommittee, it was under consideration by the House Commerce health subcommittee, chaired by Paul Rogers. Known around Capitol Hill as "Mr. Health," Rogers was one the House's most skillful legislative craftsmen. But his subcommittee needed from May unitl October to complete its work on an amended version of the Carter plan, and Rogers found that the political air had changed.

"The independence of the members . . . you can't count on them in the 94th and 95th congresses," one of Rogers' aides commented. "Four years ago, Paul Rogers would work it out with subcommittee members. It became high unholy treason to amend a committee bill. But we didn't even have all of our members on this - we lost the us-against-the-world syndrome that Rogers is usually able to cultivate. It worked in the past, but it has become increasingly difficult."

By the time Rogers' subcommittee had acted, the health subcommittee of the Ways and Means Committee was preparing to move. Energy, taxes, Social Security and welfare revision, among other things, had taken much of the committee's time until then.

And by then, Rostenkowski, the subcommittee chairman, saw trouble ahead. He never much liked the idea of mandatory controls, bu tin any case, he wasn't going out of his way to do favors for Califano.

Califano earlier had refused to follow Rostenkowski's suggestions for a couple of high-level SEW appointments. The congressman was chafing over that and, while he denied it was a factor, it gave him one more good reason not to be keen about mandatory cost controls.

"We needed hospital cost-containment," he said, "but the attitude of my colleagues here gave me every indication that it wouldn't fly. It could not be passed."

Rostenkowski had another idea. He challenged the hospitals to voluntarily restrain their costs and came up with a bill that called for federal controls offer two years if the voluntary effort failed.

Even with that moderate approach, he had problems in his subcommittee. The hospitals detested the trigger in his subcommittee. The hospitals detested the trigger and were telling legislators about it. Rostenkowski's prestige - as deputy whip he ranks fourth in the House hierarchy - was suffering.

Alternately begging and threatening, he got two subcommittee votes he needed, but the scent of disaster was in the air.

By Rostenkowski's count, the bill could not make it through the conservative Ways and Means Committee. He and Rogers then took a new tack. They would move the bill to the full Commerce Committee, get it passed - they thought - and win leverage for votes in Ways and Means. Califano agreed to go along.

"Then it became do-or-die for the industry in the Commerce Committee and they smelled the sweet fragcance of victory and they went for it," Rostenkowski said.

The scene at Commerce was chaotic. Markup sessions dragged on for six weeks in June and July. Amendments cam by the fistful. Hospital lobbyists itensified their calls on members.

Rogers and other Democrats pushed for quick action but Rep. Harley Staggers (D-W. Va.), a benign chairman, let the committee move on its own course. He once adjourned the panel when delay-minded Republicans insisted on attending Flag Day ceremonies.

The opposition had every chance to stir the waters. One of the stirrers was David Stockman, a first-termer who, on his own, developed an array of statistics and data to show why he felt mandatory controls would not work.

Like many of the 95th Congress's newer members, Stockman knew which bells to ring to make the system work for him. He had been an aide to Rep. John B. Anderson (R-Ill.) and was director of the House Republican Conference before his election.

His idea was that cost controls on the hospitals was the wrong approach. Rather, he argued, a limit on the so-called third-party payments - from health insurers, that is - would push costs down.

"My real design was to offer amendments to dramatize and point out that the whole approach was defective. I wanted to allow it to sink of its own weight," he said.

Stockman's freedom of movement symbolized one of the big changes in congressional procedures. Another change - the larger, bright staffs behind the members - showed up at the same time.

A committee member working just as fervently on the other side was Rep. Andrew Maguire (D-N.J.), another second-termer with a Harvard Ph.D. in his background. Maguire, like many other members, had built himself a cadre of staff specialists who knew how to ask questions and get answers.

He had help on the hospital bill and other health measures from full-time assistants hired for their expertise and from no-cost fellows from the Robert Wood Johnson Foundation which makes help available to members.

One thing that means is that their ideas become the congressman's translated into debate or amendments.

Joe Onek, a presidential assistant on hospital cost matters, noted the impact of the larger staffs and the expert fellows on loan to Maguire and other members.

He went to have lunch with Maguire one day and ended up in something akin to a seminar. Maguire took his experts along to lunch. "Members of Congress are no longer rubber stamps," Onek said. "Their staffs have more ablility. Even when they agree with you, it slows things down."

If institutional change was slowing the process, the medical-hospital lobby had more elbow room for working its influence. Each day of committee delay gave the lobby one day more to work on the fence-straddlers.

Among the targets was Russo, who denied the lobbyists affected him but who, nonetheless, voted the way they wanted in his surprise reversal at the Commerce Committee last summer.

Russo's vote became a cause celebre, not so much because of his independence but because of the way he expressed it. He never told his old friends, Jimmy Carter, or Paul Rogers that he would bail out at the last minute. When he did, it left hem in the helpless bind of having no time to convrt anyone else.

The last time Russo told the president about his position, Carter had turned him around - collecting on the political debt from 1974, as it were, when Carter had campaigned for Russo. Carter pleaded and Russo changed his position on natural gas deregulation - allowing the president's plan to win by one vote in the committee.

But Russo didn't like the pressure. "On the hospital thing, I was in agony as to whether I should tell him or not. If I told him, he would have used everything at his disposal to change me around. That's why I wasn't interested in calling him and getting all that pressure," he said.

The hospital experience left Russo somewhat bewildered. Carter later was quoted in the Chicago papers as saying that Russo "betrayed" him. In a meeting with other congressmen, Carter pointed at Russo and told how, by one vote, an important bill had died.

And then Juanita Kreps, the secretary of commerce, canceled a seminar meeting with businessmen in Russo's district. Democratic campaign officials let it be known that Russo wouldn't be getting any financial help this year.

"The administration just doesn't know how to handle things," Russo said. "I would have made Marty Russo feel so bad he'd have been there with the administration the next time. If they're trying to punish me, they're giving me all the help in the world."

"They really don't understand the politics," he continued. "This is a very independent Congress - it doesn't vote the party line. The younger members - Democrats and Republicans - vote their district more and more. If the issue merits, I support it."

There was no doubting that this was a different kind of Congress, but in the view of Andy Maguire, it wasn't administration ineptitude or the free-for-all spirit at the Commerce Committee that did it in Plain and simple, he said, it was the power of the hospital lobby.

"Those negative votes were more a reflection of the concerted lobbying effort of those who were affected.They were here all the time, even though I was not with them. They just kept coming back," Maguire said.

That's how Califano saw it, as well - an uphill struggle against a lobby that only time and education could overcome. "The educational process is getting through," he said. "We'll be way ahead next year. . . . We just underestimated the extent to which we had scratched a big money tree."

The medical lobby's money for congressional campaigns was only a part of it. As Califano would learn, the money tree's roots of influence reached into nearly every community in the country. The tree would not be toppled with ease.