HONG KONG — North Korea demonstrated last week that it knows how to blow an atomic-bomb-size hole through the hot air and pretensions of the so-called rulers of the world. U.S. President Barack Obama was exposed as the outraged huffer and puffer in chief against North Korea's nuclear test, but he was in good company with other leaders who condemned the North but did nothing practical to deter it.

Pyongyang's behavior is more serious than the tantrums of an unruly brat seeking attention. What is at stake is the peace and security of the whole world. China, just as much as the United States, Japan and South Korea, should take careful note and lead the search for a more realistic way to react.

While Obama was promising unspecified "international action" and U.S. Secretary of State Hillary Clinton was threatening unknown "consequences" against North Korea's "belligerence," old Korea hands were urging cool heads and caution.