Their number is up

The South Korean government of President Lee Myung-bak had barely dared hope to find hard evidence of North Korean guilt,however strong its suspicions. In doing so,it pushes the belligerent regime in Pyongyang into a corner. True to form,it continued to deny its involvement on May 20th,calling the investigation a fabrication and threatened all-out war if new sanctions were imposed.

Diplomats say it will also make it harder for North Korea s main ally,China,not to accept the regimes culpability. A senior official in Beijing reportedly called the incident very unfortunate. He did not comment on the investigation,though an official in Seoul said Chinas ambassador was briefed on the results on May 18th.

In coming days China will come under pressure to issue a tougher response,during what could be some uncomfortable diplomatic meetings. Hillary Clinton,Americas secretary of state,is to visit Beijing on May 24th and 25th. Following that,the leaders of China,South Korea and Japan are scheduled to hold a summit in South Korea on May 29th and 30th.

The proof of North Korean involvement,say diplomats,may help South Korea and its allies persuade China to back some form of United Nations condemnation of the attack. South Koreas allies such as America,Japan,Britain and Australia were quick to express their outrage. But the toughest condemnation,in the form of a Security-Council resolution,needs Chinas support,or at least abstention.

Beyond diplomatic measures,South Koreas retaliatory options are relatively puny and dangerous. South Korean diplomats suggest that the government may announce a halt to remaining business ties with the North,except through the cross-border industrial complex,known as Kaesong. It may close a shipping shortcut to North Korean vessels,and conduct joint training exercises with American maritime forces in the Yellow Sea.

A retaliatory strike,which some hawkish South Koreans are calling for,is something the pro-business President Lee is considered reluctant to do for fear of escalating the conflict. His party faces local elections that it is expected to win on June 2nd (his liberal opponents already accuse him,perhaps unfairly,of using the incident for political ends). After that he hosts an important G20 summit in November.

Among the population at large,there seems little stomach for a fight. Indeed,despite a national outpouring of grief,the senseless attack aroused surprisingly few public demonstrations of wrath with the North. Brian Myers,a writer on North Korea,notes that there was more palpable anger in 2002 when an American army vehicle ran over two South Korean schoolgirls.

However,he and other North Korea watchers think tough measures may eventually be called for. The more the cash-strapped regime in Pyongyang feels economically isolated,the more it is likely to step up its provocations against the South unless it is decisively put in its place,Mr Myers says. As it is,the North is in desperate economic straits. Six-party talks that aimed to encourage it to give up nuclear weapons in exchange for cash are stalled indefinitely as a result of the torpedo attack. International sanctions have hit other sources of hard currency.

China is its economic lifeline,as was shown again when Kim Jong Il,North Koreas dictator,made a hasty trip to Beijing not long after the Cheonan incident to beg for continued economic support. At that point,Beijing had an excuse,in public at least,to take his claims of innocence at face value. It no longer does.