The buzz around town is that President Bush may name former Assistant Atty. Gen. Viet Dinh to replace John Roberts on the U.S. Court of Appeals for the District of Columbia. Having fled Vietnam with his parents in the 1970s, Dinh went on to graduate from Harvard Law School. Now a professor at Georgetown Law School, the 37-year-old Dinh is a member of the Federalist Society and is considered a strong conservative. He helped author the Patriot Act.