The federal grand jury investigating the Valerie Plame affair today indicted Dick Cheney's chief of staff, Lewis "Scooter" Libby, for perjury, making false statements, and obstruction of justice. What is a grand jury, and what does it do? In 1998, Bruce Gottlieb explained the role and composition of grand juries, in connection with the end of Kenneth Starr's Whitewater investigations. "Grand juries make the initial decision to indict—formally accuse—a criminal defendant and require him or her to stand trial," he wrote. "Grand jury indictments are required for all federal felonies. About half the states have some sort of grand jury hurdle, too. Grand jurors are ordinary citizens who listen to the prosecutor questioning witnesses. Unlike a trial, a Grand Jury proceeding is private, and there is no cross examination or presentation of the defense case. In fact, witnesses may not even have a lawyer present during questioning. And jurors themselves may ask questions."