SEOUL, NOV. 9 -- A former chief of staff of the South Korean Army today endorsed opposition leader Kim Young Sam in a move that appeared likely to bolster Kim's candidacy in the presidential campaign by suggesting he may find significant support in the military.

Kim's supporters said the endorsement by Gen. Chung Sung Hwa, who was ousted and jailed after the 1979 coup that brought the current regime to power, would strengthen their argument that Kim's moderate views would keep the military from meddling in politics after the election.

The announcement was made at the nominating convention of the Reunification Democratic Party, which Kim heads. The convention unanimously selected Kim as the party's presidential candidate.

"My humble hope is to restore the honor of the armed forces through the realization of true civilianized politics," said Chung, who was a four-star general and the most powerful military officer in South Korea before his ouster. He has joined Kim's party as a "permanent adviser."

"I will do my best to help Kim Young Sam win the election so that a just and clean government is born," he said.

Chung joined Kim at the convention hall, and delegates cheered as the two raised their arms in victory salutes. Chung and Kim then led a protest march on the main boulevard in Seoul, chanting antigovernment slogans.

Many political analysts and western diplomats here agreed that the surprise announcement undercuts both of Kim's main election opponents -- Roh Tae Woo of the ruling party, and Kim Dae Jung, who left the Reunification Democratic Party two weeks ago to form a new party and run as its presidential nominee.

"It proves {Kim Young Sam's} claim of having support among the military," said a western diplomat. "It helps improve his credibility as someone with a broad base of support."

The issue of military support is a sensitive question in the South Korean election campaign. On the one hand, the two Kims deride Roh, a former general, as being too close to the Army and favoring a continuation of "military rule." But the Kims also want to show that each has some supporters in the military who would act as a brake on any attempted coup if Roh is defeated.

Roh, who helped lead the 1979 coup that brought Chun Doo Hwan to power, argues that, as a military man, he is best qualified to ensure that the restless armed forces will not intervene before or after the December election. It will be the country's first direct presidential contest since 1971, when then-president Park Chung Hee narrowly defeated Kim Dae Jung.

Now, Kim Young Sam can counter Roh's argument, pointing to the support of one of the country's best-known, although deposed, military men. Chung is said to retain strong links with many generals in the Army, still commanding their respect after seven years in the political wilderness. Moreover, Chung is something of a political martyr to some South Koreans who see him as a military man who opposed Army intervention in politics.

Today's endorsement of Kim Young Sam by Chung also is seen as a blow to Kim Dae Jung, who has long had a reputation as a radical whose election might prompt military intervention. Kim Dae Jung has tried to combat that reputation by recruiting former military officers into his political camp.

Chung's role in Korean politics was brief but notable. After president Park was assassinated in 1979 by the head of the Korean Central Intelligence Agency, Chung declared martial law but pledged to hold presidential elections. He is said to have opposed direct military control over politics.

Six weeks later, troops loyal to Roh and Chun surrounded Chung's house and, after a shootout, arrested him as an accomplice in the assassination of Park. Although the charge was widely regarded as baseless, Chung was given a stiff jail term by a military tribunal, but he was released on parole after less than two years, ostensibly for health reasons.

Special correspondent Young Ho Lee contributed to this article.