In the middle of an interview last Monday, Bang Myung-hyun's phone rang. His friend, Kim Sung-hoon, the ex-president of Yonsei University's student association, had just been arrested under South Korea's National Security Law.
"If somebody in South Korea agrees with North Koreans, is that 'benefiting the enemy'?" the student leader asked.
The government thinks so. It worries that activists like Mr. Kim and Mr. Bang, who express views often espoused by North Korea, could help Pyongyang by suggesting disunity over how to deal with the communist adversary to the north.
Despite a return to democracy, South Korea has kept its 48-year-old National Security Law, under which people can be punished for praising or traveling to the North, praising communism, or importing or exporting information to or from North Korea. Even Internet Web sites praising the North are blocked. To repeal the law would sow "social confusion," officials say.
In fact, officials say, "leftists" are getting bolder, prompting a crackdown. Over 102 people have been arrested since May, according to a group founded by families of political prisoners called Mingahyop.
It might seem strange that students in South Korea, with its economic dynamism and democratic reforms, would have much truck with the bankrupt and Stalinist regime in Pyongyang. But the students' position has less to do with ideology than with nationalistic sentiments. They are overwhelmingly concerned with the emotional idea of reunifying the Korean peninsula, divided since the end of World War II. Many students believe the division remains because of the influence of foreign powers on the Seoul government, not Pyongyang's intransigence.
"At least North Korea has its own government, not one based on a government of ex-Japanese officials," says a student at Yonsei University who requested anonymity. When Korea was liberated from 35 years of Japanese colonial rule after World War II, North Korea purged all collaborators with Japan. But South Korea let people who were trained by the Japanese run the country.
Park Chung Hee, military dictator of South Korea from 1961 until 1979, now seen by some as a hero for leading South Korea's industrialization, was an Imperial Japanese Army officer. "How would you feel if George Washington had collaborated with the British?" asks one student.
South Korea also grew with the help of American military protection, loans, and technology. The students complain that Washington has tactical control over both the American and the South Korean armies, and that it uses its military presence in Korea as political leverage, promoting its own interests like arms sales, and protecting American soldiers who commit crimes here. "The South Korean government is backed by the American government, and so [it] must act in accordance with America's will," says Bang.
Antigovernment activists say, much as Pyongyang does, that Seoul is a puppet of America, and joke, if somewhat angrily, that South Korea is the "51st state."
North Korea, on the other hand, although poor, is admired for its proclaimed self-sufficiency. Lacking outside influences that follow international trade, North Korea keeps the Korean language and cultural traditions more intact, students say.
BEFORE communism collapsed in the Soviet bloc, and South Korea shed its dictatorship, such idealistic nationalists were more common. And nationalism often earned students some public sympathy.
Now many here agree with Kim Tae-woo, an independent lawmaker who calls himself a "strong anticommunist," and who says students are no longer "a threat at all" to national security. North Korea is too concerned with food shortages and a failed economy to pursue its old strategy of instigating unrest and revolution in South Korea, he says.
So why the crackdown?
For one, North Korea hasn't renounced aggression, and the threat of spies persists. Last month the public was shocked when a professor at Dankook University, Mohamed Kanso, turned out to be a North Korean spy.
"They are not students, they are professional revolutionaries," says a professor of national ethics at a prestigious Seoul university. They are "potentially very powerful." An accountant in Switzerland, he says, channels South Korean students North Korean funds and they also receive instructions from the North. The have a presence at over 165 universities and, "If people think [the students] are silly, then the students are very tactically successful."
But mostly it makes Seoul uncomfortable to have young people parroting North Korea's official stands, such as a separate peace treaty between the US and the North. Many older conservatives in the government who remember the war "become very nervous at these types of things", says Woo Jae-sung, president of The Freedom Center, a think-tank in Seoul.
Seoul would prefer to see issues of reunification solved between itself and Pyongyang.
Students are gearing up to jangle the government's nerves again on Aug. 15, the 51st anniversary of liberation from Japan. Last year's event attracted upwards of 20,000 people. Just as Tuesday's protest of 400 did, it will attract copious amounts of riot police and pepper gas as well. That protest was sparked by the arrest of Kim Sun-hoon.