There's a good reason why censorship sparks so many squabbles, as developments in both China and the Muslim world this past week have reminded us. It's a slippery concept. We who favor openness and transparency think we know exactly where we stand on censorship: We think it's bad. Right? Freedom of speech is a vital pillar of democracy, and all that. And that is true. But it's not necessarily the only truth.

We are sometimes brought up short by news of real-world situations in which a little censorship -- or at least self-censorship -- might be a better thing than people saying, showing or printing whatever they want to. There is no single rule. As the wise say, it all depends.

Most of the time the familiar view is the right one. Chinese officials were wrong, for instance, to bar the Hollywood movie "Memoirs of a Geisha" from Chinese cinemas last week. For one thing, the ban will be ineffective. Though officials offered no reason for the move, it followed nationalist demonstrations in Beijing and other cities this month against the movie's casting of Chinese actresses as Japanese geisha. Organizers claimed this was somehow insulting in the context of Japanese wartime atrocities. But if the government's idea was to avoid further "negative social response," as the film company put it, it can forget it: Pirated DVDs of the movie have been available in China for weeks. The Chinese will see it anyway.