Alarm bells are ringing inside the White House, the State Department and the Pentagon. The U.S. Embassy in Seoul has warned that South Korea's presidential campaign is getting nasty and could incite violence at the polls.

This could cause a serious miscalculation by North Korea, whose rabid ruler, Kim Il Sung, is itching to stir up trouble below the border. If the election is disrupted by street violence, Kim might interpret this as an opportunity to intervene.

He isn't expected to attempt another invasion of South Korea. More likely, he would flood the country with agitators and terrorists who would try to whip the political fracas into a civil war.

Intelligence reports portray the implacable Kim as seething with envy and bitterness. He has been growing old against a backdrop of crumbled ambitions. South Korea's economy is booming; North Korea's is stagnant. South Korea is holding a democratic election to pick its next leader; Kim is trying to foist his son on North Korea as his successor.

Next year, South Korea will gain international recognition by hosting the Olympic Games. North Korea has become increasingly isolated, and Kim's campaign to stop the games has failed. There have been intelligence warnings that he will lash out to disrupt the games. One report suggested that his terrorists might even sabotage air traffic to discourage fans from attending the Olympics. The recent downing of a Korean Air Lines jetliner, with 115 aboard, has been attributed to a terrorist bomb.

What worries U.S. authorities is that the South Korean election could be so close that the losers won't accept the results. If ruling-party candidate Roh Tae Woo should win a squeak-through victory, the opposition candidates will claim the election was rigged. If left-wing candidate Kim Dae Jung should triumph, the army might lose its patience and intervene.

Then this whole exercise in democracy could move from the polling booths into the streets, and South Korea could be added to the State Department's list of foreign-policy disasters. For the policy-makers in Washington seem to be preoccupied with appearances in Korea and unconcerned about avoiding another Iran-style, foreign-policy forfeiture that could change South Korea from a weapon of the West to a cannon pointed at Japan.

Above the 38th parallel, Kim Il Sung still refuses to sign a treaty, and the Korean war is frozen in time. Meanwhile, he has built up an army of 800,000 men, the sixth largest in the world, which has been preparing for 35 years to reinvade South Korea.

South Korea's military dictatorship, for all its shortcomings, has brought stability and increased prosperity to the country and is now keeping its promise to establish civilian democracy. Meanwhile, the government has cooperated with American defense policies, welcomed American enterprises and supported American foreign policy.

None of this apparently has earned the government any points from its critics. And the man who persuaded and pressured the military rulers to set a free election, Roh Tae Woo, is more damned than praised.