Stuart Buck links to an interview with leading Supreme Court advocate Carter Phillips, who observes that Clarence Thomas is hardly unusual, even by the standards of recent history, in rarely asking questions at oral argument:
When I argued in 1981, you could pretty much bet you weren’t going to get any questions from Justice [William] Brennan [Jr.], and you might get one question from Justice [Thurgood] Marshall. Justice Blackmun would ask a question that you weren’t always sure you were quite ready for because you could never quite understand necessarily what the purpose of the question was, although I think he usually had one. And my old boss, Chief Justice Burger, very rarely asked one. I don’t think he ever asked me a question at all in the years that I argued there.
Of course, Thomas’ detractors, who use his silences to paint him as a stupid man, are generally huge fans of people like Brennan and Marshall.