He is a freshman senator, a campaigner who wins by whopping margins, a legislator beloved in his home state and looked askance at by some Hill veterans. He is 37 years old, unmarried, and counts among his regular dates a 50ish Washington TV show hostess.

Party hostesses delight in having him as a dinner guest, and he has developed an appreciation of Washington social life.

"He's very sought after," said one friend of his. "He's young, handsome, a good conversationalist, intelligent. He has everything."

Not yet. Now, Sen. Larry Pressler (R-S.D.) is intrigued by the idea of running for president, a notion proffered, he says, by some friends.

These friends, who have formed the Pressler for President Committee, have scheduled a press conference for this Thursday to announce their plans.

Never mind that Pressler has been in the Senate only six months. After all, this was the man who won his first House seat as a Republican in 1974 during the height of Watergate, who got a record majority for his second election to Congress, and who once won the student body presidency at the University of South Dakota even though he wasn't a fraternity man.

"I think he has a kind of vision," said Connecticut Avenue lawyer Paul Arneson, organizer of the soon-to-be official Pressler for President Committee. "He can say no when no is required, and he can say yes when yes is required."

"To my mind," said one former congressional aide," he exemplifies what's wrong with our political structure - winning at the expense of holding consistent views. It's a brilliant tactic." $&(WORD ILLEGIBLE

Now, he is one of a crop of young, attractive, media-savvy congressmen like Tim Wirth (D-Col.) Sen. Don Riegle (D-Mich.), Sen Bill Cohen (R-Maine), and Sen. Max Baucus (D-Mont.). Like Pressler, they probably one day will have friends who will splurge on a committee urging their names for the presidency, tapping them as much for their attractiveness and burgeoning image as anything else.

Up From the Farm

Pressler grew up the American success story on a Humboldt, S.D., farm. When he was in school he worked as a hired hand on the dairy farm of a neighbor who has now shelled out money for the presidential committee. Pressler climbed successfully through 4-H and the University of South Dakota earning his way to an Eastern life style with Harvard law school and a job as a State Department counsel. Before law school, he won a Rhodes Scholarship but left it after 18 months for the Vietnam War.

Pressler is image-perfect. His suit was the requisite pin stripe; his tie is in the club fashion.

"It's the U.S. Equestrian Team tie," he said, reaching down and looking at the little crests. "I was the chairman of the Equestrian Ball."

Pressler calmly takes in all that has been said about him. "One newspaper said I had a "promotional genius and a flair for drama," he said, looking up innocently wide-eyed in surprise. "I'm known to be almost dull, because when I speak, I go right to the issues and skip the homilies."

He's also known to be a master of the media, turning out press releases to the local home papers regularly - some on issues he's involved in, others on things like how his mother is being recognized for her work ("...Loretta Pressler has painstakingly handwritten thank-you notes to all who have given financial contributions to her son's campaign....")

"He may not have gotten up last February on the Senate floor to say much about the American Agricultural Movement," said one Hill observer, "but he rode in on a tractor with a South Dakota farmer and got his picture on TV - much to the envy of his colleagues."

He shows up frequently in South Dakota (once a week when he was in the House) spending time with the farmers, gas pumpers and coal miners....

"He's covered South Dakota like the dew," said one high-ranking aide to Sen. McGovern. "He'd drive a tractor with a farmer and have his picture taken. And there's definitely a double standard. McGovern is judged on every colon and comma. In this office we have to be extremely precise, otherwise everyone will be on our rear ends. But Pressler isn't called to account for anything. When he's interviewed by the local press, it's like they're interviewing the accordion player on Lawrence Welk, instead of someone who has a record to account for. Geez, I admire the guy for getting away with it."

Earning His Spurs

"Haven't they given you an office yet?" Sen. Jake Garn (R-Utah) asked with a grin, spotting Pressler sitting on the couch outside the Senate floor.

Pressler laughed delightedly. He speaks cheerfully to all the senators who pass him on their way to the floor.

"I've been favorably impressed with every senator I've met," said Pressler. "Particularly I think a lot of Howard Baker and Barry Goldwater. I play tennis with Howard Metzenbaum."

He is concerned about how his "colleagues" take this business of possibly running for the presidential nomination. "One senator asked me in the gym the other day, if I win, could he be secretary of state," said Pressler, smiling. "It's been taken in a humorous vein."

"I think this whole thing may be a little premature," he said about the Pressler for Presidency effort."I haven't been out beating the bushes."

But it's something he's thought about. "These people [on the committee] will go back to their home states and see what kind of financial commitments they can get. I wouldn't be seeking the traditional support. It would be a rather quixotic campaign, based on issues. It certainly wouldn't be based on money. But people are a little turned off by direct mail, anyway."

He's calculated what it will take. "With 10 Republicans in a primary, there is a belief that lower than 20 percent will win some of the early primaries - maybe 18 to 25 percent of the vote will win the primaries."

His outer office is papered with crayoned drawings of little figures and houses done by South Dakota youngsters for whom Pressler sponsored an art contest. Those whose art work is sent in get little copies of the Constitution fro; Pressler's office.

Inside his office is a framed color photograph of the family farm in Humboldt.

"There's a period of time over which you earn your spurs," he said. "I'm still somewhat in awe of the Senate."

He talks at length about his favorite projects - rail deregulation, vocational education, senior citizens, small businesses. For someone who has blazed his way through his elections, he is surprisingly low-key. There is a polished understatement to his mannerisms and his looks: brown tousled hair and an eager smile as he walks on and off the Senate floor.

"I'm trying very hard to establish a good reputation," he said. "Whenever people meet me they've always read the Wall Street Journal piece, so I'm trying extra hard."

The story in the Wall Street Journal of May 20, 1977, dealt Pressler a hard blow after only five months in the House. WSJ reporter Albert R. Hunt examined the new congressman's attendance at committee meetings and record on substantive issues and concluded that "As a campaigner, he is superb.... But as a legislator, Mr. Pressler isn't much."

Pressler defended himself in a letter to the editor, claiming his attendance record was among the best. He's still defending himself.

"I'm sure there are things I did wrong in the allocation of my time, I'm sure there are things I still do wrong," he said, "but when that story was researched I was a freshman Republican congressman. You don't get your name on much when you're a freshman from the minority party."

Waffling

But some believe his greatest problem is that he waffles. "We once spoke at the same meeting of some very angry farmers during the farm strike of the winter of 1978," said former Sen. James Abourezk, whose seat Pressler took when Abourezk retired. "I spoke about the bill I was introducing in the Senate, then Larry, who was a congressman then, got up and said he was working hard on the Talmadge bill, and people had to be patient. A woman in the back yelled out, "We like the Abourezk bill." So Larry immediately said, "Okay, I'll introduce the Abourezk bill in the House when I get back. Sure, politicians can waffle and change views. But in the same meeting?"

Pressler said that was not exactly the way it happened. "For one thing there wasn't that much difference between the two bills," said Pressler. "It wasn't inconsistent to be interested in both."

Still, Pressler is portrayed by some as a senator who simply doesn't make up his mind on issues until the end. "He seems to be influenced by the debate on what he's talking about - even as he's talking about it," said one Hill observer. "He keeps his mind unmade up until the last minute - more than most senators."

Pressler generates a flurry of activity. He runs to his office on the Hill each day from his Watergate South apartment. For fun, he roller skates ("I learned in 4-H") and plays tennis.

"He's much quieter than he was in the House," said one Hill observer. "At his best he's shy. He seems to be growing very tentatively in the Senate. He digs in, does his homework, and he's not hotdogging. This presidential stuff sounds like the pre-Senate Pressler."

His influence in the budget committee, which he sits on, has been rated by some as modest at best.

"He did indicate to me once that the transition from Congress to Senate was more startling," said Sen. Alan Simpson (R-Wyo.), another freshman senator. "He felt there was no much more required of you in the Senate in the way or participation and grasping the issues. In the House you had the luxury of more time."

"A Kind of Wunderkind"

But Pressler has glided pleasantly into Washington life.

He has wined and dined around town with the best of Washington society. Shortly after he won his Senate race, Sen. John Heinz III (R-Pa.) gave him a fund-raiser in his lavish Georgetown home at $125 a head. Cosponsors included Charles Percy and Howard Baker. "It was wall-to-wall people," said Washington TV-show hostess Deena Clark, who dates Pressler. "In all the years I've been in Washington I've never been to a fund-raiser like that."

Clark, who says Pressler is "brilliant," goes with him to dinner sometimes at the Pisces Club or to parties. "People used to call me for parties and say, "Bring an escort." Now they say, "Bring Larry.""

Clark, who is a veteran of Washington TV, is not bothered by the age difference between Pressler and herself. "Younger people are very stimulating. People don't look at us funny. They may look at us - but not funny."

"He's very serious-mined," said Ina Ginsberg, a prominent Washington hostess who is a friend of Pressler's and has given a dinner party for him. "He's very interested in meeting people who know Washington, who would help him formulate his ideas."

Some of those friends have included the late Walter Hodge and his wife Margaret whom Pressler got to know since he became congressman.

Pressler's friends speak highly of him. "I had been around the party circuit and the limelight, and I didn't need it," said 36-year-old Harriet Dent, a former model, a former secretary to Rep. Tom Railsback of Illinois, and now a researcher at the Congressional Office of Tecnology and Assessment. "I made a rule not to date congressmen. Women are always fawning all over them. When you're in high school, you can do that game playing. You don't need it at 36. But I broke my rule for Larry. He was down to earth and so personable. And he works very hard. I guess he's kind of a wunderkind to have come so far so fast."

"Larry's a Leader"

Paul Arneson has supreme faith in Larry Pressler. That is why the blond, tanned Connecticut Avenue lawyer invited friends from all over the country late last month to his rambling Adams Morgan house to present Pressler with the proposal that he run for president.

That's why he has also begun raising money - successfully - and why he is on the verge of hiring a couple of people to help with the committee work.

"I think we'll persuade him to run," said Arneson, sitting in his office. "If I didn't think we had a chance, I wouldn't have done this. Larry Pressler's chances for 1980 are at least as bad as Jimmy Carter's were four years ago."

Arneson, in his mid-30s, has an easy laugh and a relaxed manner. One wall of his office is a deep, dark blue, the same color as the shirt he wore. "Ever since I've been in a position to, I've had at least one wall in my office that color," he said grinning.

Arneson, who has known Pressler, although not well, for six years, organized the committee with people like himself - young lawyers and businessmen plus some friends of Pressler's from South Dakota. "We're feeling our oats, and we're ready to get involved in something like this - Larry's a leader," said Arneson.

Pressler has known for some time that this committee would surface. "He's been intrigued with the idea since I first mentioned it to him earlier this year," said Arneson. "A lot of other people talked to him about this."

One of the people who did not talk to him about it was one of Pressler's most significant financial backers in the past elections - South Dakota businessman Max Pasley, a wholesale appliance distributor and the franchise owner of all four McDonald's in Sioux Falls. "I just haven't researched the issue enough," said Pasley in a phone conversation about the possbility of Pressler running for president. "What with the tourism down and the grasshopper problem, we've got so many other things on our minds here."

In the Dark

Pressler sat through 20 minutes of a lunch with two SALT lobbyists and his aide, Doug Miller, who asked most of the questions. Pressler, who is undecided about SALT, then excused himself to go to a meeting.

"What's this business with him running for president?" one of the lobbyists asked casually.

"I really don't know anything about it," said Miller, a soft-spoken man and longtime Pressler friend who has taken two years off from his job as a political science professor at Northern State College in Aberdeen, S.D., to work for Pressler. He looked around akwardly. "Frankly none of his staff know about it. I don't think it's being taken seriously. My own idea is that it's damn silly."

One Last Waffle

"You know I've been through five campaigns in four years," said Pressler, waiting in the Senate reception room for some activity on the floor. He ticked off a number of primaries and generals in the course of two congressional races and one Senate race. "If they say I've been acting like I'm campaigning, well, they're right. I've had so many campaigns, I really want to work on being an effective senator now."

He looked at his watch and realized another lobbyist was waiting to see him. One more question, he is asked. Are his eyes blue or gray?

He smiled. "Well, look at them and see," he said.

They look gray, but what do you think, he is asked again. What do you put down on your driver's license - blue or gray?

"Blue-gray," he said, and walked away smiling. CAPTION: Pictures 1 and 2, Larry Pressler; by James K. W. Atherton - The Washington Post