The head of the National Intelligence Service, Kim Man-bok, resigned after admitting that he had leaked a document regarding a secret visit to Pyongyang he made one day before last month's presidential election.

Kim's visit to the North was reported earlier this month, and the Presidential Transition Committee subsequently requested a briefing on the matter. He provided a written document to the committee on Jan 8; the following day, he telephoned a JoongAng Ilbo journalist, offering him the document, on condition that it would not be reported. The same afternoon, an NIS official delivered the document to the journalist. The document, not surprisingly, was reported in the newspaper the next day.

The memo, which details a conversation between Kim and his North Korean counterpart Kim Yang-gon, shows the NIS chief briefing Kim on the possible outcome of the election. He also speculated that the new administration would continue with inter-Korean economic cooperation, and that it may be easier for the next president to rally support for inter-Korean initiatives.

Kim said he released the secret document in order to clear suspicions that the NIS tried to use North Korea to influence the presidential election in the South. That may be, but the document clearly shows Kim attempting to curry favour with the incoming administration. This is not surprising, given the fact that he is suspected of having ordered background checks on Lee and his close aides in 2005 and 2006. The NIS is also suspected of having masterminded the return from America of Kim Kyung-joon, president-elect Lee's former business partner, for investigation into possible stock manipulation and embezzlement, in an attempt to influence the presidential election.

At a press conference announcing his resignation, Kim said he felt responsible for causing this controversy. However, this was not the first time that he was mired in trouble. He caused a stir last year when he flew to Afghanistan to direct the negotiations with the Afghan rebels for the release of Korean aid volunteers, and then appeared in the media with the freed hostages. Kim's actions revealed the Korean government's direct involvement in the hostage negotiations, and exposed the whereabouts of the country's chief spy to plain view.

Kim is not the first spy chief to be involved in a controversy. Several of his predecessors were sent to prison for various crimes, including instigating political operations, ordering illegal wiretapping, and accepting corporate bribes.

It is unfortunate that the NIS's reputation has been soiled again and again by the inappropriate conduct of its leaders. As president-elect Lee Myung-bak considers candidates to head the NIS, he must carefully review their personal integrity and leadership capabilities. Appointing anyone who cannot rise to the challenge of leading an organisation with a very special mission would be a great disservice to the men and women of the NIS who are dedicated to serving this country.

In addition, the spy organisation must be granted political neutrality. The incoming administration should do more than pay lip service to the NIS' political neutrality. Mechanisms must be instituted that will ensure that the spy organisation does not become involved in domestic politics.

A crucial question remains unanswered concerning the latest NIS controversy: Why was Kim in Pyongyang just one day before South Korea's presidential election? The conversation between him and his North Korean counterpart, as conveyed by Kim himself, is surely not the whole story. Prosecutors need to investigate the matter.