One is an ageing North Korean cargo tub with more than one previous owner and a record of weapons trafficking. The other, shadowing the Kang Nam 1 as it chugs slowly round China's coast on its way, it is believed, to a port in Myanmar via the Malacca Strait, is an American guided-missile destroyer, bristling with up-to-date radars and weaponry. But it is to be hoped that the captain of the USS McCampbell, reportedly taking over the tracking from a sister ship, the USS John McCain, has at least one old-fashioned bit of naval kit on board: a bullhorn.

The American ships are doing UN-approved duty. Resolution 1874, passed unanimously by the Security Council on June 12th permits the searching of North Korean cargoes on vessels on the high seas suspected of carrying illegal arms shipments. But, in what seems a nose-thumbers' charter, it requires the flag-owner's consent, which in this case is highly unlikely to be forthcoming. If the Americans cannot direct the Kang Nam 1 with stern words to a nearby port for a search, they will have to hope a shortage of fuel forces it to dock.

The new restrictions on North Korea limit its weapons imports to small arms, and ban all arms exports, conventional or otherwise. They followed a provocative long-range missile test and last month a defiant claim of the country's second nuclear test. Puzzlingly, sensors failed to detect telltale gases that usually leak out within days of such a test, but that could be because North Korea is, troublingly, better at testing small nuclear warheads deep underground than observers had guessed.

... contd.