PAUL BRUHN CAME to Washington in 1975 as one of the youngest (27), least experienced (none) top aides to a senator. In a short time, through long hours and hard work, he had earned the respect of his colleagues and counterparts on Capitol Hill as a smart, innovative administrative aide.

As alter ego to newly elected Sen. Patrick J. Leahy (D-Vt.), Bruhn could look forward to a long run in national politics.

But after 3 1/2 years, Bruhn packed it all in and went home to Burlington, Vt. He gave up the White House briefings, diplomatic receptions, cocktail parties, French restaurants, reserved underground parking space and 14-hour days.

He and his wife, Kathy, who was Leahy's office manager, traded in a combined annual income of $69,000 for the slower pace of life on the shore of Lake Champlain.

"Washington was everything I expected it to be," Bruhn said during an interview in one of those trendy Hill restaurants, shortly before he quit last summer. "It has been exhilarating, challenging, rewarding -- and not for me."

Now, five months later, he is able to say, in a telephone interview from Burlington, that he has no regrets.

His former boss, Leahy, said "Paul never really wanted to leave Vermont. Finally, I talked him into it, with a commitment to come for no more than one or two years. He already was a year beyond his absolute deadline."

Shortly after Leahy's surprise victory over the state's at-large Republican representative, Richard W. Mallory, Bruhn, who had managed Leahy's campaign, came to Washington to put together a staff.

Bruhn's initial impression -- which never changed -- was that the staffs of first-term senators remained "sensitive to the people back home." But the longer they had been here, the less concerned they were for their constituents.

Bruhn pledged then to "make an extra effort not to fall into that trap." But affer a few years here, he came to believe that the insensitivity "may be inevitable."

In an attempt not to become stale or remote, Bruhn, with Leahy's encouragement, went to Vermont at least one weekend a month, and in August 1977, the entire staff transferred to Vermont for a working vacation from which they returned "absolutely rejuvenated," Bruhn said.

But back here, Bruhn found it "difficult to remain fresh, an almost impossible task."

"If you do the job right, the way it ought to be done, it's all-consuming," he said. "You eat, drink, sleep the thing, and you burn out."

Bruhn also tried to fit in socially. He discarded his corduroy jacket, jeans and hush puppies occasionally for a threepiece suit. And he and Kathy grew to enjoy the city, and looked forward to weekends exploring its museums and the surrounding countryside.

But during the work week, his disillusionment grew.

Bruhn recalled one illustration. Rural health legislation was one of Leahy's pet projects. To get a first-hand look at the need for appropriations, Bruhn and some other congressional aides visited a clinic in St. Charles, Va. which had requested a $15,000 grant from HEW.

"After looking over the operation," Bruhn said with a grimace, "one of the bureaucrats decided to up the ante to $75,000 in the form of a loan."

When one of the clinic's volunteers said they didn't need that much, and suggested they might have trouble repaying the larger amount, the volunteer was told "don't worry. We'll get HEW to waive the requirement that it be repaid," Bruhn said.

Leahy met Bruhn when Leahy was prosecutor of Chittenden County (Burlington) and Bruhn was editor and publisher of a financially troubled city magazine that he had founded. Some articles about consumer fraud written by Bruhn caught Leahy's eye, so when the prosecutor decided to form a consumer protection division, he asked Bruhn to run it.

And when Leahy decided to run for the Seante, he asked Bruhn to be his campaign manager.

Bruhn remembers the campaign as "my best work experience. Patrick, which is what all of Leahy's staffers called him, worked his butt off. We all did. It was possible to work 16, 18 hours a day because we had a specific goal -- to win -- and we knew it was all going to end on a specific date."

Bruhn believes the campaign he directed "operated best because I had never done it before," and that first-term senators and their staff also have the same advantage.

"Paul ran a brilliant campaign," Leahy said. "One newspaper called it 'the children's campaign," and said we were doing it all wrong. Neither of us had the traditional preparation for a Senate race. If we both had, neither of us would have gotten here."

But once candidate Leahy became Sen. Leahy, "the goal was more ethereal -- call it good government -- and there was no end in sight," Bruhn said.

The idea of coming to Washington with Leahy "didn't occur to me," Bruhn said. "For one thing, at no time did we assume we were going to win."

But when Leahy offered his top spot to Bruhn, he took it. Suddenly Bruhn, a college dropout who had never made more than $12,000 a year in his life (and that was for Prosecutor Leahy) had a $37,000 salary and a $500-a-minth townhouse in Old Town Alexandria.

Because he had no legislative experience (he once ran unsuccessfully for the Vermont legislature), Bruhn sought to employ experienced Hill staffers. His first hire was Herbert A. Jolovitz, who had been AA to Ohio Sen. Stephen A. Young for 12 years, and then to Ohio Sen. John J. Gilligan.

Jolovitz, who now is with Gilligan at the Agency for International Development, recalled that Bruhn said he didn't intend to stay a full term. "I told him, 'Oh sure, I've heard that before.' But he's walked away from it. You very rarely see that happen, especially with someone who was so solid with his boss."

During their time here, Leahy said, "Paul became one of my closest and dearest friends. Day in and day out, he had total and complete access, as much as anyone except my wife."

Jolovitz suggested that "Paul may be part of a new breed, someone who wants to get something accomplished, but who is not thinking of making it a career."

Another person Bruhn hired was Kathy Stankevich, a journalism graduate of American University from Springfield, Vt. She quickly advanced from assistant press secretary to office manager, becoming "the gule that held the place together," Bruhn said.

Eventually Bruhn "violated my own office anti-fraternization rule," and on June 25, 1977, Bruhn and Kathy were married.

By the time they quit last summer, Bruhn's salary had risen to $49,000 and Kathy's was $20,000.

And Bruhn could quit "with the feeling that I did a really good job. I learned a great deal and saw some goals accomplished."

So with $5,000 in savings, they went home to Vermont, having confirmed Bruhn's preconceived notion that Potomac Fever might be contagious, but that it is also a disease that can be avoided.

The decision to return to Bermont wasn't as easy for Kathy as it was for her husband. "I love the city," she said at the time. "I came here to get away from Vermont. But I'm ready to go back. If you go home, you realize the world doesn't stop. Other people are accomplishing things."

They knew they would have to take a substantial pay cut, but they have fared better than they anticipated, although their income now amounts to less than half their Capitol Hill salaries.

"But our needs are less," Bruhn said. Instead of dinner twice a week in expensive restaurants, "we take a jug of wine to the home of friends." And whereas a movie in D.C., with parking, could cost $10-11 for two, it costs $5 in Burlington.

And because they are where they want to be, there are fewer weekend excursions, although they manage to get to Montreal or Maine occasionally.

A major concern, Bruhn said, was "that I'd wind up with one job, instead of having 17 balls in the air as I had in Washington, and I'd go stir-crazy."

Nevertheless, he has managed to accumulate an eclectic collection of part-time projects, the bill payer of which is a halftime contract with the National Trust for Historic Preservation.

He also has time to work as a volunteer, a luxury he couldn't afford here. He worked in the successful campaign to elect Democrat Madeleine Kunin as Vermont's new lieutenant governor, and donates time to a program designed to strengthen downtown Burlington's position as a regional shopping area.

Kathy is working for a ski manufacturer and learning to cross-country ski.

Their one big disappointment, which they hadn't thought about, is that they no longer work together.

Bruhn vows that he'll never return to Washington, and that he'll never seek public office. But he is sympathetic for those who do go into politics, having been on the receiving end.

"I'm fearful, however, that those of us in Burlington, and Des Moines, and wherever, are putting too many demands on public servants. We expect too much."

He was reminded of the day early in 1978 when three major projects came to fruition. Leahy had managed to get his rural health legislation passed. He won reappointment for a Vermonter to the joint international commission that regulates Canadian-American affairs and he saw a federal grant awarded to Montpelier.

"But there wasn't moment to sit back and savor those successes," Bruhn said. "There were 17 other crises awaiting our attention.

"I need time to say, 'Damn, that was neat.' Up here, I've got time to watch the sunsets."