ONE of the students at my university was killed in the attack that sank a South Korean naval vessel on March 26. A visual communications major, Mun Yeong-uk was only a few months from concluding his military service when a North Korean torpedo split the warship, the Cheonan, in half. His classmates loyally collected money for his family’s funeral expenses, but I was struck by how few people on our campus evinced any real anger toward the regime of Kim Jong-il.

This lack of indignation is mainstream here. Most people now accept North Korea’s responsibility for the sinking that killed Mr. Mun and 45 other sailors. A small but sizable minority suspect an elaborate government conspiracy of some sort. What almost all seem to share is the desire that South Korea put this unfortunate business behind it as soon as possible.

Support for military retaliation appears confined to those too old to fight. Even the rather mild measures that the South Korean president, Lee Myung-bak, announced on Monday — which included the drastic reduction of inter-Korean trade and resumption of the propaganda war along the demilitarized zone — have caused widespread hand-wringing.

The general reluctance to take the North Koreans to task can be partly attributed to a rational apprehension of the military realities. No one here needs to be reminded that Kim Jong-il could bomb Seoul flat even without using his new nuclear capacity. And in a country where all fit young men must spend two years in the military, “chicken hawks” are much harder to come by than in America.

But historical and cultural factors are also at work. By this I do not mean only the collective memory of the Korean War and its manifold horrors. Up until the late 1980s, right-wing governments resorted to North Korea scares so often that many people now refuse to believe any stories about the regime, no matter how overwhelming the evidence. If President Lee thought he could allay doubts with an especially thorough investigation into the sinking, he was mistaken. Left-wing newspapers now accuse him of postponing the announcement of the investigation’s results to exert maximum influence on next week’s regional elections.

It would be unfair to characterize these skeptics as pro-Pyongyang, but there is more sympathy for North Korea here than foreigners commonly realize. As a university student in West Berlin in the 1980s, I had a hard time finding even a Marxist with anything nice to say about East Germany. In South Korea, however, the North’s human rights abuses are routinely shrugged off with reference to its supposedly superior nationalist credentials. One often hears, for example, the mistaken claim that Mr. Kim’s father, Kim Il-sung, purged his republic of former Japanese collaborators, in alleged contrast to the morally tainted South.

Sympathy for Pyongyang is especially widespread in the peninsula’s chronically disgruntled southwest, and not just because this farming region profits whenever food aid is sent to the North. Gwangju, the largest city in the region, just commemorated the 30th anniversary of a brutal government massacre of civilian demonstrators, many of whom were defamed in the official news media of the time as North Korean agents.

South Korean nationalism is something quite different from the patriotism toward the state that Americans feel. Identification with the Korean race is strong, while that with the Republic of Korea is weak. (Kim Jong-il has a distinct advantage here: his subjects are more likely to equate their state with the race itself.) Thus few South Koreans feel personally affected by the torpedo attack.

Besides, Koreans in both the North and the South tend to cherish the myth that of all peoples in the world, they are the least inclined to premeditated evil. The sinking of the Cheonan is widely viewed here as an almost spontaneous byproduct of inter-Korean tension — a regrettable aberration that should not be made too much of. The left attributes the recent increase of tension to President Lee’s rejection of his predecessors’ accommodationist Sunshine Policy. Yet even the conservative news media talk of the attack in terms of an “error” that the North should own up to, not a cold-blooded act. Students in my classes tend to refer to the sinking as an “accident.”

This urge to give the North Koreans the benefit of the doubt is in marked contrast to the public fury that erupted after the killings of two South Korean schoolgirls by an American military vehicle in 2002; it was widely claimed that the Yankees murdered them callously. During the street protests against American beef imports in the wake of a mad cow disease scare in 2008, posters of a child-poisoning Uncle Sam were all the rage. It is illuminating to compare those two anti-American frenzies with the small and geriatric protests against Pyongyang that have taken place in Seoul in recent weeks.

Such are the unique circumstances under which President Lee has tried to marshal a firm and unified response to the North’s latest provocation. So far he has done an excellent job, conveying just the right mixture of resolve and restraint. Where American presidents tend to personalize conflict with foreign powers, Mr. Lee refrained from explicitly blaming Kim Jong-il for the sinking; this may make it a little easier for the dictator to issue an apology without losing face.

Even as the North threatens “all-out war,” the Obama administration would do well to emulate the South Korean leader. It should be mindful enough of Korean nationalism to hold back on its own rhetoric. It would be counterproductive if Washington were to look more interested in punishing North Korea than the injured party is.

B. R. Myers, the director of the international studies department at Dongseo University, is the author of “The Cleanest Race: How North Koreans See Themselves — and Why It Matters.”