The artist Ai Weiwei vanished at Beijing airport two days ago on his way to board a flight to Hong Kong. His assistant said he was taken away by border guards; since then there has been no word of his whereabouts. It must be assumed that Mr Ai, who has become an ever more vocal critic of human rights in China, is in the hands of the authorities.

There are times and places where international fame can serve as protection from persecution by the regime. Today's China is not one of them. That Ai Weiwei has an acclaimed exhibition at the Tate Modern in London seems not to have helped him at all. When the imprisoned dissident Liu Xiaobo was awarded the Nobel Peace Prize last year, the Beijing authorities did nothing to hide their displeasure, detaining his wife into the bargain and preventing her from travelling to Oslo for the ceremony. International opprobrium was not a consideration; months later, she remains under house arrest.

Since unrest began to sweep the Arab world at the start of the year, Beijing has shown itself increasingly impatient with its critics, rounding up dozens in raids that smack of nothing so much as paranoia. Rather than treating its world-ranking artists and thinkers as an adornment, whose creativity and advocacy reflect well on China, the knee-jerk response of the regime is to regard them first and foremost as a threat to internal stability – an attitude which risks becoming a self-fulfilling prophecy. In so doing, the regime seems to be wilfully blind to its own best interests.

By spiriting away someone as celebrated as Ai Weiwei, who is known in his home country also for helping to design the Bird's Nest stadium that became the pride and glory of the Beijing Olympics, the authorities may hope to deter other, so far more tentative, dissidents from speaking out. In China, they might have a measure of success, though Ai Weiwei has shown an admirably stubborn refusal to be intimidated. But this makes it all the more beholden on the Western world to keep track of those in China who dare to press for change, and make the strongest possible representations to Beijing on their behalf.