THE idea of a United States helicopter accidentally straying into North Korea during a routine training mission on a clear winter morning is so far-fetched that even Hollywood might find it difficult to swallow. The demilitarised zone between North and South Korea is four kilometres wide and heavily fortified, and even a pilot celebrating Christmas a few days early would have difficulty failing to spot the dangerous no man's land below as he headed north. Whatever the US helicopter was doing a few kilometres north of the border, it is to be hoped that Pyongyang will show mercy to the two men on board, even if it is disinclined to give them the benefit of the doubt. The world has come a long way since North Korea captured, tortured and imprisoned for 11 months the crew of an American spy ship, the Pueblo, in 1968. While North Korea itself has not changed that much, Pyongyang officials have proved adept at exploiting the opportunities presented by the end of the Cold War. North Korea ran rings around the US, for example, over Pyongyang's nuclear programme. Earlier this year, President Bill Clinton appeared to take the peninsula to the brink of war, but when Pyongyang refused to budge, the US effectively offered North Korea US$4 billion in return for its promise to honour international commitments. If a promise no one believes is worth US$4 billion, Pyongyang might be forgiven for viewing its two hostages as, potentially, a rich source of income. The best hope for the US is that the top levels of the North Korean regime recognise the benefits of freeing the pilots - in terms of propaganda and international goodwill - would outweigh any advantages - in terms of intelligence or ransom payments - that might be derived from detaining them for any length of time. A complicating factor, however, is the incomplete transfer of power from the late Kim Il-sung to his son, Kim Jong-il. Nonetheless, the last thing anyone needs is a heightening of tensions on the Korean peninsula, and self-interest alone means North Korea would be well-advised to appear magnanimous by defusing a crisis that, if it exploded, could destroy not only the nuclear accord, but North Korea as a nation, generating tensions that could affect the peace, stability and development of northeast Asia for many a year.