SEOUL, JULY 11 -- South Korea may soon conduct its first contested election since 1971, and the capital is buzzing with the normal sounds of democracy: political gossip, factional scheming, whispered insults about rival camps.

The sounds are welcome in a nation where military coups and martial law often have made politics irrelevant. But the jockeying is also deadly serious, for rivalries and ambitions long suppressed from above must now resolve themselves in a few weeks or months.

None is being watched more closely than the undeclared contest between longtime opposition leaders who are known here simply as "the two Kims": charismatic Kim Dae Jung, 63, and party leader Kim Young Sam, 59. For two decades they have been allies and rivals, fighting military-imposed governments at considerable personal cost while jostling for leadership within the opposition.

Now, after waiting so long, they both see their chance. But they also know that, if neither backs down, they will likely split the opposition vote and hand the presidency to ruling party leader Roh Tae Woo.

Yang Soon Jik, a vice president of the main opposition Reunification Democratic Party, said that despite widespread worries there will be no split. "They will not apply the past style to the future," he said. "The two Kims know that if they cannot solve the problem together, they are both finished."

If one Kim does emerge as candidate of a united opposition party, his prospects would be good -- but by no means certain -- in a fair head-to-head election, most observers here believe. Any prediction is risky, in part because so many Koreans have come of voting age since the last election and in part because no one has been turned out of office peacefully since the republic was formed in 1948. The government has promised elections in the fall, but no date has been set.

The ruling Democratic Justice Party promises stability and continued economic growth and offers experienced talent not found in the main opposition party. In a nation where local officials down to village chief are appointed by the central government, the ruling party controls a powerful machine funded by businesses that have prospered with government help.

And by agreeing to elections and reforms after weeks of street protests in June, the ruling party hopes it has co-opted the opposition's strongest issue: democracy.

The chief beneficiary of this is Roh, the architect of the unexpected government turnaround. Roh was a general and a military classmate and longtime Army colleague of President Chun Doo Hwan, but he also is blessed with an ingratiating manner and an open, pleasant face that Koreans see as distinctive from the dour, stern demeanor of the president. Many believe that Roh could be an impressive vote getter.

But against a united opposition, all of that might not be enough.

"You'd be asking voters to forget what's been serious dissatisfaction with the pace of democratic reform under the ruling party," one western diplomat said. "It's sort of the opposition's election to lose -- and they could blow it."

The Kims enjoy the goodwill of many voters for their years of battling for democracy. They promise a more open system, with a free press, no political prisoners, no torture and less government guidance of the economy.

But neither Kim will find it easy to defer to the other.

"They competed, really rather viciously, for the nomination in 1970-71, when Kim Dae Jung won, and in 1980," when the military intervened, another diplomat said. "So I think there's no love lost between them."

The two Kims do not seem far apart on issues, although Kim Dae Jung is usually said to be somewhat to the left. In fact, a western diplomat said that neither Kim's policies would likely change abruptly from those of the ruling party. Both support the continued presence of U.S. troops, 41,000 of whom are here.

"The RDP {main opposition party} doesn't represent labor, doesn't represent farmers, doesn't represent the urban poor," the diplomat said. "It's a conservative, business-oriented party."

Certainly, though, there are few similarities in style.

Kim Dae Jung won 45 percent of the vote against Park Chung Hee in 1971, an election that he says he would have won had there been no fraud. Since then, he has been jailed, sentenced to death, forced to live in exile and placed under house arrest dozens of times. For seven years ending only this week, he was barred from making speeches and was never interviewed on television. Only when widespread protests erupted last month did his photograph begin to appear in some newspapers.

"When it comes to politics, to campaigning, no one can touch him, no one else comes close," a Korean bureaucrat who does not support either Kim said yesterday. "If he speaks for 30 minutes, everyone is on his side."

Kim Young Sam, with his dapper suits and winning smile, has been more the inside man of the opposition. He, too, suffered for his efforts, being thrown in jail for brief periods and spending more than two years under house arrest, but he largely has been permitted to remain within the system.

His supporters say this makes him better suited to run the government, more moderate and less likely to seek revenge for past offenses. Kim Dae Jung's supporters say their man alone has the depth, the credentials of the struggle and the weight of authority that a president needs.

None of the sniping is public, of course.

The Kims insist that they will remain united, agreeing on a ticket within a month or two.

"We are two different persons, with different places of birth, different educational background, different upbringing -- it's natural to have differences between the two of us," Kim Young Sam said in an interview. "But we have always come to a meeting of minds, through dialogue, in spite of our vast differences."

Said Kim Dae Jung: "There will be no split."

For the moment, though, both Kims are behaving like candidates. Kim Dae Jung promised last fall that he would not run if Chun allowed direct elections, but this week he said changed circumstances have nullified that pledge.

The government, meanwhile, is gearing up for its campaign. President Chun this week ceded day-to-day control of the party to Roh, and a Cabinet shake-up is expected this week to streamline the government for the election.

The "third Kim," former prime minister Kim Jong Pil of the ruling party, said this week that he, too, "is ready to receive the people's judgment." Other candidates soon may emerge.

For now, though, it is the two Kims of the main opposition party who are being watched.

Some worry that if the two Kims leave their choice of who will run unresolved for a long time that some voters will become impatient and turn away.

"Kim Dae Jung is a driven man," the western diplomat said. "But they're not fools, either. I think that in the end there'll only be one candidate.

"But I worry a little that by then people will be so fed up that the damage will be done."