DEBATE still simmers about a remarkable intervention in the domestic politics of Malaysia late last month by China’s ambassador in Kuala Lumpur, Huang Huikang. A few days after the police had resorted to water cannon to disperse ethnic-Malay protesters shouting anti-Chinese slogans in the city’s Chinatown, he visited the area and made a statement calling for racial harmony. China “will not sit by idly”, he said, if its citizens’ rights are violated or Malaysian-Chinese relations damaged. The sentiments seem unexceptionable in themselves, if a bit puzzling, since the Chinese living there are almost all Malaysian citizens. But the public gesture seemed to flout the most hallowed tenet of Chinese foreign policy: not to interfere in other countries’ internal affairs. In fact, that principle has always had limits and, where ethnic Chinese are concerned, sometimes seems not to apply at all.