In the autumn of 1985, three years before the Olympic flame was scheduled to be lit in Seoul, South Korea, Robert Helmick, president of the United States Olympic Committee, was given a tip. It wasn't good news. Then again, it certainly was not unexpected.

Helmick was advised that the Seoul Games, like the past five Olympics before them, would be touched by politics.

"We were aware of the implications of a transition in the government of South Korea," Helmick said this week. "Knowledgeable people, experts in Korean affairs, told those of us in the Olympic movement to expect some events in relation to the elections. As it turns out, what happened was all predictable."

Two weeks ago, Helmick was visiting Seoul to make plans for the U.S. team's trip to the Olympics, still 15 months away. In addition to meeting with officials and inspecting sites, he found himself watching demonstrations in the streets in protest of the government of President Chun Doo Hwan. The predictions had come true.

First, there was the continuing dispute between North Korea and South Korea over the hosting of some Olympic sports, a problem that will be further discussed at meetings that will begin Tuesday at International Olympic Committee headquarters in Lausanne, Switzerland. Now, there were demonstrations.

But Helmick was far from distressed. While some persons outside Olympic circles publicly have wondered if the Olympics should be held in Seoul -- and cities around the world are clamoring to take the Games from South Korea -- Helmick remains unflinchingly optimistic that the show in Seoul will go on.

To wit: He said it took him two days to "locate" a protest march during his recent visit, and when he watched, he said he "felt perfectly safe." The city's glistening Olympic facilities were left untouched by the unrest. And he said he got the strong impression that everyone involved in the disputes realizes that if the Olympics had been about to begin, there would have been no demonstrations at all.

"There was no threat to property or person 100 yards from the demonstration. It certainly was not like what happened in Watts or at the Chicago Democratic Convention," Helmick said. "Frankly, I put this in the same category of traffic problems and smog problems in Los Angeles, or the demonstrations that the Russians were expecting had they come to L.A. The Olympics have become such large events that we have to be used to public speculation about the various ways they might occur." War Clause

Helmick is not alone in his thinking. IOC President Juan Antonio Samaranch said the other day the Olympics will be held in Seoul from Sept. 17 to Oct. 2, 1988, "or there will be no Games at all." It is written in the Olympic charter that the only reason for moving the Olympics is war. No one in the Olympic movement believes that clause will be enacted next year. Also, so much preparation has already been done by the hosts, individual Olympic committees and the media that "it would not be possible to move the Games this close to the date," Helmick said.

The past month or so, newspapers and television newscasts have shown countless pictures of mobs in the streets of Seoul and tear gas in the air. The news from Seoul, even after the government's concessions last week, has been frightening. Two have died. Hundreds have been arrested.

Yet, talk to members of the Olympic community and the picture changes dramatically. Perhaps numbed by the almost inevitable mixing of politics with sports, Olympic officials here and abroad have spoken in unison in favor of Seoul and its Olympics. Violence, demonstrations, terrorism: what's new, they say. It's not good, but it has happened before. Their view is the Olympics will go on, just as always.

Some remember with a smile the concerns about Los Angeles in 1984, including fears out of Western Europe about how their athletes would cope with an earthquake in Southern California. "All you have to do is say the word 'Olympics' and a minor news story becomes big news," Helmick said.

"This is nothing new," said Anita DeFrantz, a member of the Los Angeles Olympic Organizing Committee in 1984 and one of two U.S. members of the IOC (Helmick is the other). "I'm confident the Games will be in Seoul."

In fact, in an ironic twist, there even is a strong feeling in the international sports community that the 1988 Summer Olympics might become the greatest showcase of international sports ever. Every Summer Olympics since 1968 has seen political intervention, and the last three have been hit with boycotts: In Mexico City, troops gunned down hundreds of protesters less than two weeks before the '68 Olympics; in 1972, Palestinian terrorists killed 11 Israeli athletes in Munich; in 1976, Montreal's economically troubled Olympics were hit by a boycott of black African states; in 1980, the United States and some of its allies boycotted the Moscow Olympics, and, in 1984, the Soviets returned the favor by leading a boycott of the Los Angeles Olympics.

Right now, the only country likely to boycott Seoul is North Korea, and that will happen only if it doesn't get its way in the dispute over hosting events. (It's possible other communist countries will boycott if North Korea does, but officials don't consider it likely at this time.) North Korea wants to host eight of the 23 sports; South Korea is offering archery, table tennis and parts of soccer and cycling.

Assuming no other country joins North Korea if that nation boycotts, Seoul will play host, simply, to the world's biggest sports spectacle ever.

"These Olympics have the prospect of being the most successful Games technically, and in terms of participation," Helmick said.

The thought is staggering, especially to the athletes.

"One of my biggest regrets in 1984 was not having the East Germans there," said swimmer Mary T. Meagher, 22, who won three gold medals in Los Angeles and is planning to compete in Seoul. "I'm a competitor at heart. One of my biggest reasons for staying in swimming until 1988 was to get a chance to go against the East Germans in an Olympics. I'm going to keep my fingers crossed that that happens." Mutual Influence

It appears the prospect for the biggest Olympics ever exists because the Olympics have as strong a pull on the politics of a nation as politics have on the Olympics themselves. Last week, Chun stunned many observers by agreeing to the protesters' call for a full democratic process. After one month of violent protests, the situation has stabilized somewhat. It's considered likely that the Olympics had a large impact on Chun's decision, which was precipitated by a speech by ruling party chairman Roh Tae Woo.

"Now that the Olympics are approaching, all of us are responsible for avoiding the national disgrace of dividing ourselves and thus causing the world to ridicule us," Roh said June 29.

"One of the factors that forced the government concessions was that it was very embarrassing to them to see other countries come forward and offer to host their Olympics," said Ralph Clough, an expert on Asia at Johns Hopkins University's School of Advanced International Studies. "The government leaders certainly didn't want to risk losing the Games."

Clough, who recently finished writing a book entitled, "Embattled Korea: The Rivalry for International Support," said internal political dissension was the overriding reason for the concessions, with the threat of losing the Olympics the second most important factor.

"The Olympics are so very important to the Koreans," Clough said. "You can't talk to a Korean without the subject coming up. It's almost as if they don't think about anything after 1988" . . .

The organizers in Seoul have lofty aspirations for their Olympics, which were awarded to them Sept. 30, 1981. It is their hope that they can impress the world in 1988 the way Tokyo did in 1964.

More than anything, South Koreans want to eradicate what could be called, somewhat playfully, The "M*A*S*H" Factor. South Koreans never liked the passive, relatively unimportant role they played on the popular television show. "They say, 'We are the ones who fought the war,' although the show didn't make it look that way," Clough said.

To that end, the organizers of the Olympics have put on an impressive entrepreneurial display that would make Peter Ueberroth proud. They have spent an estimated $3 billion on the Games. New facilities abound, a majority of which were ready in the autumn of 1984, four years before they were needed. Sleek hotels have sprung up, reaching for the clouds. The banks of the Han River, which runs along Seoul's Olympic Park, have been spruced up. Organizers even picked a civic-minded motto for their Olympics: Harmony and Progress.

There is an historical precedent for believing things will quiet for the Olympics. Last year, political uprisings took place in Seoul immediately before the Asian Games, the city's trial run for the Olympics. A bomb exploded at the airport six days before the Games began, killing five and injuring 31. (South Korean authorities blame Communist agents for the attack.)

When the Games began, however, the violence ended. A truce was called by government and opposition leaders until the Games were over.

Those in the Olympic movement are quick to point out they are not belittling South Korea's political advances when they speak so optimistically about the chances of the '88 Olympics.

"I'm not an expert in foreign affairs, but it seems to me {the concessions} are a very significant event for a developing nation," DeFrantz said.

What Olympics officials are saying is if politics and sports must be intertwined, they hope it can be for the good of both.

Said Helmick: "Perhaps it's good that we are hearing about the changes in South Korea and learning about their system. Controversy is not new to the Olympics, but I look at this as controversy in the positive sense. Issues are being brought up that should be brought up, and if the Olympics helped to do that, that's good."