Dear Leader,

South Korea sends a firm but measured message to the North

May 24th 2010 | From The Economist online

SEOUL

LEE MYUNG-BAK, South Korea's president, has shown impressive restraint since the Cheonan, a South Korean warship, was sunk on March 26th. Now that the investigation into its cause has reached a conclusion however, he faces a dilemma. The 46 sailors who went down with their ship and the North Korean insignia found in the spent torpedo's propulsion system demand a bold response. Yet Kim Jong Il, North Korea's leader, is so unpredictable that it is hard to know where that might lead.

In his televised address on Monday, Mr Lee talked tough, referring to North Korea as the “most belligerent regime in the world”. Shortly after Mr Lee's address, his ministers of unification, foreign affairs and defence laid out practical responses that South Korea will now take.

Their retaliatory measures are to go further than many expected. In addition to referring the matter to the UN Security Council, South Korea will ban North Korean vessels from its waters and cease all economic ties—save for those at Kaesong, a jointly run industrial complex. The South also plans to take part in the Proliferation Security Initiative (PSI), a multinational naval operation aimed at blocking the spread of nuclear materials. The North has always been especially wary of the PSI and until now the South had dithered on committing to it. To add insult to these injuries, Mr Lee's government announced plans to resume the "psychological warfare" it had stopped in 2004. This consists mainly of spreading anti-Communist propaganda in the form of leaflets and radio broadcasts aimed across the border

South Korea's allies are standing no less firm; several have already condemned North Korea while expressing support for the government in Seoul. America is reviewing punitive measures of its own while Hillary Clinton, its secretary of state, is trying to persuade China to agree to more strident UN sanctions. She visits Seoul later in the week. Japan's prime minister, Yukio Hatoyama, cited the threat posed by North Korea as a justification when it came time for him to renege on his campaign pledge to remove an American marine base from Okinawa.

Impoverished and isolated, the rulers in Pyongyang have one last lifeline: China, which keeps North Korea supplied with everything from food to electricity. Mr Kim paid a visit to his comrades ahead of the Cheonan fallout. Ostensibly the visit reaffirmed the two countries' solidarity. China now finds itself in the awkward position of having to pick sides between the Koreas, which it is loth to do. The diplomatic pressure will increase as Wen Jiabao, China's premier, visits Seoul on May 28th to meet Messrs Lee and Hatoyama.

Mr Kim is adept at deflecting such pressure, however. In a clever move calibrated to appeal to China and to South Korea's liberals, the North has renewed its protestations of innocence and demands that the South invite a North Korean inspection team to examine the material evidence. The South’s defence minister scoffed that this would be like asking a burglar to come and inspect the scene of the crime. But if the South continues to dismiss this request, it might inadvertently provide China with the escape it is desperately seeking.

To overturn the investigators' verdict would require meeting a high bar indeed, such as proof of the whereabouts of North Korea's submarines at the time of the attack. In the absence of such counter-evidence, China may have to take a firm hand with North Korea, shifting the balance of power in what many regard as the world's most alarming stand-off.