Even in home region, S. Korea's Roh isn't sure thing. A candidate's native region used to determine his success. Today, voters' age, their desire for stability, and worker discontent will decide if Roh Tae Woo, the only declared candidate, will win. Hometown reminisces about Roh, P. 12

Regionalism is a potent force in South Korean politics. The region around the city of Taegu has produced two presidents and hopes to produce a third, Roh Tae Woo.

But in the presidential election to be held before the end of this year, regionalism intersects with other factors to muddy predictions.

The strongest of these factors is the nearly universal desire for democracy after 26 years of authoritarian military rule. Second is the youthful composition of voters and third, the middle-class concern for stability. A fourth, nascent factor is worker discontent.

All four factors can be observed here in Taegu, a city of 2 million in the southeast corner of Korea and capital of North Kyongsong Province.

So far, Mr. Roh, standard-bearer of the ruling Democratic Justice Party (DJP), is the only declared candidate, and if regionalism were all, he would be the overwhelming favorite. He comes from a village 10 miles from Taegu, and attended Taegu's famous Kyongbuk High School.

Again, if regionalism were the only factor, the most probable opposition candidate, Kim Dae Jung, would not stand a chance in Taegu. He comes from Cholla, a province that occupies the southwestern corner of Korea. The rivalry between Kyongsong and Cholla goes back for more than a thousand years, when both were the seats of independent kingdoms. It has been particularly acute in recent years, when Park Chung Hee and Chun Doo Hwan, the two presidents North Kyongsong has produced, tended to favor their province over Cholla in terms of economic development and patronage.

But a graduate of Kyongbuk High School now in Seoul says that the democracy factor could work against Roh, even in Kyongsong. ``It depends on how people perceive Roh,'' he said. ``Will he be seen as ... a crony of unpopular, autocratic President Chun? Or as the hero of democracy, the man who quieted weeks of civil unrest by his June 29 speech proposing democratic reforms ... ?''

An editor at the Taegu Daily News shook his head in perplexity. ``Normally this is a conservative city,'' he said. ``But 60 percent of the voters are in their 20s and 30s. And because of industrial development, there are many workers here from other parts of the country. It's impossible to predict the outcome of the presidential election.''

Another local journalist, agreed that with more young people voting, regional rivalries were not as important as the overwhelming desire for democracy and civilian rule, a factor that should favor Kim Dae Jung. And yet. ...

``Suppose Kim Dae Jung kicks off his campaign in Kwangju, capital of South Cholla. Suppose the people there enthusiastically support him, saying that after two presidents from Kyongsong it is time for Cholla to produce the next president. That kind of approach would most certainly reawaken regional feelings here, even among the young.''

The strong middle-class desire for stability is another factor that will cut across regional rivalries, not only here in Taegu, but across the nation. Roh made his June 29 proposal, and Mr. Chun was forced to accept it, because the middle class had turned against the government and supported the civil disturbances. It was not that the middle class wanted unrest; mainly they were tired of military rule and wanted to be able to vote for whomever they liked.

Once that was conceded, however, the middle class has been divided, uncertain. Some will stick with Kim Dae Jung as the champion of democracy. Others, even in parts of Cholla, fear that the military, which remains a potent force, may stage a coup d''etat if Mr. Kim wins.

What of the final factor, worker discontent? One-fourth of the electorate is made up of industrial workers.

A man I will call Mun Sang Chol is a foundry worker in Taegu. He works 10 hours a day, six days a week, and makes about $400 a month. ``This is not by choice,'' he said. ``It's the only way I can make a decent salary.''

``My factory is owned by a member of the Democratic Justice Party,'' Mr. Mun said. ``I suppose he will put pressure on us to vote for Mr. Roh. I don't intend to give into that kind of pressure, but I'm not sure others will.''

An older worker, listening to this conversation, sighed. ``Yes, we all start out with ideals,'' he said. ``But when you have a family and kids, you give up your ideals.''

Across the nation, worker discontent has already flared up in dispute after dispute since the transition to democracy began following Roh's June 29 speech. It is difficult to predict how things will develop after campaigning starts in earnest. Will Kim Dae Jung, for instance, consciously try to fan this kind of discontent? Might this in turn alarm the middle class?

Pessimists abound. ``There is so much pent-up feeling, by so many people - the democrats, the Cholla people, the workers, to say nothing of students,'' said a Christian opposition leader. ``This election is going to be a kind of exorcism.''

But there are optimists as well. ``Until Roh made his June 29 speech,'' a DJP assemblyman said, ``the whole nation was in an uproar.... The minute he made it, everything quieted down. Of course, now our party has to carry out its promises of democratic reform. But I think the electorate is wise enough to see that we are doing so.''