It will be five years next week since Justice Clarence Thomas spoke during oral argument at the Supreme Court. Before falling into this long silence, he posed a question on Feb. 22, 2006. In the past 40 years, no other justice has gone an entire term without speaking at least once during arguments, according to Timothy R. Johnson, a professor of political science at the University of Minnesota. Can a justice effectively perform his duties without participating in oral argument? Does questioning the lawyers in court make much difference, or is it mostly a ritual, with the justices' thinking pretty...