The crisis of the Korean hostages captured by Taliban forces in Afghanistan two weeks ago on July 19 hits Korean leaders where they’re most vulnerable. The government of South Korea might have preferred not to have sent troops to either Afghanistan or Iraq but did so under pressure from America. As long as America is keeping 29,000 troops in South Korea, on guard against a perpetual threat from North Korea, the Americans believe their Korean friends should show their gratitude by joining the grand alliance in the Middle East.

Now the president of South Korea, Roh Moo Hyun, whose policy of rapprochement with North Korea has won only reluctant American support, is caught between the desire to show firm resolve and the need to win freedom for the hostages. He is running out of time. Taliban terrorists have killed at least two of the original 23 hostages and are threatening to kill the others.

The quickest way to placate the terrorists would be to arrange an enormous payoff, to release Taliban prisoners held by the government of Afghanistan and to speed up withdrawal of South Korea’s 200 troops, mostly medics and engineers, from Afghanistan. That solution would be fine by the same South Korean leftists who opposed the dispatch of South Koreans to the Middle East and have been calling for U.S. troops to get out of South Korea.

That request puts America in a difficult position. How can America ask the president of Afghanistan, Hamid Karzai, to yield to Taliban demands when America, its allies, and Afghanistan troops are fighting the Taliban? And by advancing that argument, how could the U.S. still hope to improve often strained relations with South Korea when Mr. Roh’s government is under enormous pressure from both leftists and conservatives to save the surviving hostages?

The position of America, South Korea, and Afghanistan’s government is all the more difficult since the hostages are all members of a Christian congregation that had gone to Afghanistan on a do-good “volunteer” mission.

South Korean negotiators are accustomed to dealing with the North Koreans, rewarding North Korea with infusions of aid, including heavy oil, in response to such good behavior as the shutdown last month of the North’s nuclear reactor. The enemy in Afghanistan is far different from the North Koreans, but the bottom line is the same — the Taliban holds hostages and threatens to kill them while North Korea holds South Korea hostage under the threat of a nuclear war.

The possibility of the imminent death of more members of a delegation that consists mostly of young God-fearing women dispensing medical aid is more personal and compelling than that of a nuclear holocaust. The nuclear issue is sublimated among Koreans as they focus on heart-rending messages made by hostages on Taliban cell phones.

The hostage issue is laden with implications for the U.S.-Korea alliance. The chief of the U.S. central command, Admiral Timothy Keating, who is responsible for the entire Asian region, tried to help by saying his forces would be “quick to respond” to a request from South Korea. Exactly what Americans could do, though, that Koreans aren’t already doing, other than to try to get Mr. Karzai to agree to the Taliban’s demands, is hard to see.

For President Bush, the hostage crisis in Afghanistan raises familiar issues. The question is whether or not America is trying to persuade South Korea to tough it out on the hostages. U.S. military people, of course, see the taking of hostages as a tactic that cries out for defiance. The Americans might not mind handing over a huge ransom to the Taliban, but would rather not see the release of Taliban prisoners in exchange for hostages, or the early withdrawal of South Korean troops.

Negotiations with Islamic terrorists are more difficult than those with North Korea because no one knows quite who they are and with whom to talk. Like Mr. Bush, Mr. Roh cannot risk confrontation with an enemy on two fronts — with North Korea on the Korean peninsula and with the Taliban in Afghanistan.

The Taliban may appear far weaker than the North Koreans, but they and their friends and allies in Al Qaeda are capable of acts of terrorism that are as bloody and violent as some of those perpetrated over the years by North Koreans. Moreover, South Korean negotiators have little or no experience in fathoming the minds of Arab zealots willing to kill — and “martyr” themselves — for a cause.

But there is one crucial difference between negotiating with the North Koreans and the Taliban. The Taliban may call for South Korean troops to leave Afghanistan but they aren’t asking for a withdrawal of American troops from South Korea. Nor is it likely that leftist demonstrators will take to the streets in support of the Taliban — though they are already using this episode as another reason to demand that South Korea refuse to support America in the Middle East or anywhere else, including their own country.

Mr. Kirk, who is a freelance correspondent based in Seoul, covered the first Gulf War from Baghdad and reported again from Baghdad in 2004.