How do you impose sanctions on a country that has nothing? Hillary Clinton, US secretary of state, is proposing to do just that. She says the US is preparing carefully targeted measures against impoverished North Korea. Washington is right to pursue this line. It has little other option. China, the nation with a modicum of sway over Pyongyang, has refused to condemn Kim Jong-il's regime for its March attack on a South Korean warship that killed 46 sailors. That despite the fact that an international inquiry found little doubt that Pyongyang ordered it.

Largely because of Chinese recalcitrance, North Korea was all-but let off the hook by the United Nations this month. A statement condemning the attack did not even mention North Korea by name. Chinese premier Wen Jiabao's insistence on “easing tensions” in the region amounts to acceptance that North Korea can act as it pleases. It is worth pondering what his reaction might have been if the 46 murdered sailors had been Chinese.

The US appears to be planning a rerun of measures used to block $24m of North Korean funds in 2005. Then, it froze assets deposited in Banco Delta Asia, a Macao bank accused of helping North Korean leaders launder money. These sanctions had an outsized impact. They proved instrumental in bringing Pyongyang back to six-party talks aimed at halting its nuclear programme – although the negotiations turned out to be fruitless. Still, the virtue of “precision sanctions” is that they hurt the regime, but not North Korea's downtrodden people.