Scalia has already recused himself from one high- profile case this term, which examines whether the words "under God" in the Pledge of Allegiance violate the Constitution's separation of church and state. In that case, the litigant who is challenging the pledge filed a motion charging that public comments Scalia made last year about the Pledge of Allegiance suggested bias. Scalia did not attempt to argue the point, or justify his earlier statements.
The justice has taken a different posture following the duck-hunting episode, actively defending his actions. "It's acceptable practice to socialize with executive branch officials," he told the Associated Press after a recent speech.
Details about the hunting trip are still somewhat sketchy. On Jan. 5, Scalia and Mr. Cheney flew together to Louisiana on Air Force Two. They were among others invited to a hunting camp by a Louisiana businessman. Cheney stayed for two days. Scalia hunted for four.
Judicial-ethics experts say the ride aboard Air Force Two could be viewed as an improper gift from a litigant to a justice. In addition, some say the fact that the justice and a litigant are vacationing together undermines the appearance of judicial impartiality.
Cheney's case involves lawsuits filed by a government watchdog group, Judicial Watch, and the environmental group Sierra Club. Both are seeking disclosure of information about consultations between energy officials and the vice president's Energy Task Force back in 2001. Neither group has filed a motion seeking Scalia's recusal, but Sierra Club officials say they are considering it.
The Cheney case is significant because it involves a broad assertion of executive branch authority to conduct White House affairs in secret. Some analysts say the case could result in a 5-to-4 split, or 4-to-4 if Scalia bows out.
Legal experts say the prospect that a recusal could determine the outcome of a case is one reason Congress left it to each justice to decide whether to recuse.