It was the lobby that first made him uncomfortable: the stanchions, the ropes cordoning off the public, the guard behind the desk, the sign-in and check-out forms, the bareness of the walls. The sterility of it all.

Why was all that necessary? he wondered. Why not scrap all those officious, hostile trappings of government?

Simple enough, he was told.It was to keep "them" out. "They" had tried to take over the building in the past, "they" were still out there today.They and they andthey. He listened long enough, and finally snapped:

"Look, I don't think you understand. They are now in charge around here."

In Jimmy Carter's Washington, Sam Brown occupies a special place, and role. Call him a symbol, if you will. He won't like that, but that's what he is. He's the outsider, come inside; the reformer, turned bureaucrat; the youthful idealist, practicing pragmatism.(A "young old cynic," he says of himself.)

He knows why he's here, and thinks he knows enough to know when to leave. (If so, he'll be different. Most of them keep proving Thomas Wolfe, the original, wrong. It's not that they can't go home again. They don't want to.) But most of all Sam Brown knows the game.

"I like the game," he says. "That ought not to be mistaken. I like it. This is a town full of very smart people at a whole bunch of different levels of government . . . in the administration . . . and in the Congress . . . and in the lobbying organizations . . . and in the staffs. A lot of very smart people around this town."

As he sees it, people play two kinds of games in Washington. One is a territorial aggrandizement game, the favorite of the bureaucrats and almost everyone else. The other is purely symbolic: players hold only little pieces of territory, but have lots of access. They win by their positions, not their turf. They have influence. Influence is power.

"So it's a dual thing," Sam Brown says, "territorial power or real power. And these games are going on all the time. They are really the most dangerous games in town."

Brown's symbol in other ways. When he was in Washington before, in the late 60's, many thought he stood at the center of the most exciting game.He was leading the anti-war forces, mobilizing demonstrations, planning peace rallies, getting publicity for the Vietnam moratoriums. It was a highly visible role. You could see him on the network news programs or read about him as a young political savant, seasoned already by the "children's crusade" (that foolish journalistic term) of Eugene McCarthy that toppled a president.

But he looks back on those days now and sees he had no real power. What's more, he now regards the antiwar movement as having been substantially a failure. The pictures on the tube and the articles in the papers had more to do with finally ending the war than the demonstrations, he thinks.

He came out of that experience changed. "Some of us who came here at one time with a pure burning sense of changing the world went through very cynical times about the country, about other people, about the world in general," he says. "At least in my case, I lost a lot of that early faith in some larger possibilites, and what the American people are like."

Brown didn't drop out. He didn't exactly go straight, either. But he did withdraw. He went to Colorado, ran for the state treasure's office, and won. The radical gone respectable. By all accounts, he was building an impressive political constituency and had a bright political future there.

More personally, how he lived his own private life had become increasingly important. In time he developed what his Buddhist friends call "centering" Sam Brown was at peace with himself.

Then came Jimmy Carter's call to Washington.

ACTION, one of those stirring sounding names that political hacks dream up and then foist upon the public, was hardly what its name implied. It was, in fact, the opposite: an "umbrella agency," that familiar governmentese term, to house what was left of the most liberal, idealistic and, yes, naive governmental impulses of the '60s. There, the bones of the Peace Corps, VISTA and the war on poverty rested. IN the Nixon years, ACTION became probably the most politicized, dispirited agency in town. Name notwithstanding, its real mission was to slow down and eventually dismantle the program over which it presided.

Jimmy Carter wanted Sam Brown to take over as director. Give the place a rebirth of idealism. From Brown's friends came uniformly negative advice: It's a cynical country now. College students are cold, materialistic. Nobody wants to give up anything. They're all out for themselves. All in it for a buck. That's what America's all about in the '70s.

Brown had his own doubts. "One of the things I think I know about this town is that it eats people up in human terms," he says. He also knew that for a dozen years he'd been on the opposite side of the government, always the critic, always calling for change. If he passed up a chance to see if he could make government work better, he'd probably forfeit a future political role. And he had ambitions. He took the job.

Many of them change instantly after they take their official oaths and occupy their official suites. They swell with self-importance. They literally swagger. They retreat behind a wall of secretaries. They never return calls. They adorn their private offices with plaques and pictures and proclamations attesting to their greatness. They glory in telling of their brutally long hours. They are terribly significant.

To Sam Brown's credit, he remains unstuffy and self-critical. His office is simple: a few odds and ends here and there, a bottle of Bufferin next to a Bible, on discernible grand design.

His approach to his job seems fresh, too. He'd been warned about all the political bodies buried throughout his agency, heard all the rumors and innuendo about the bitter past. Brown's not running a purge. They'll have a chance to prove themselves.

He's taken down the stanchions and ropes and eliminated the check-ins and outs. The place is beginning to blossom with personal notes on bulletin boards and on the elevator walls: everything from a transcendental meditation course to a lecture on detecting letter bombs.

Now he's got people out in the country looking at the programs he administers. Not in-house bureaucrats with a place to protect, nor hotshots newly come to town with reputations to be won. He's commissioned outsiders who live in the communities affected by those programs. His charge: tell him "what the hell this agency does that matters."

And if he finds out that none of it works, or matters? At the age of 33, he's heretical enough to say he'll tell the President and the Congress his programs ought to be broken up, or eliminated. That, of course, would place him in default on the big territorial game. "I'm not a very good imperialist," he explains.

He's already learning new lessons about the other, bigger Washington game.

"There was a picture of the President and me standing together on page 3 of The Post about a month ago," he recalls. "The next day I got telephone calls returned that hadn't been returned for days and days before."

Brown was disturbed. It was a perceived relationship that wasn't real at all. It makes you wonder how quickly you become like your symbols.

"Now, that's nonsense," Sam says.

No, it's not, Sam. That's Washington.