AVON, Colo. – U.S. Supreme Court Justice Antonin Scalia missed Thursday’s swearing in of John G. Roberts as the court’s 17th chief justice because of a two-day seminar in Colorado sponsored by the Federalist Society.A court spokeswoman in Washington said Scalia’s commitment to the previously scheduled event could not be broken. The seminar focuses on the separation of powers.Scalia was the only justice not at the White House during Roberts’ swearing in ceremony. —On the Net:Federalist Society: http://www.fed-soc.org/events/2005/scalia05/promo.htmVail, Colorado