OXFORD, Miss. — One is a sharp-tongued, self-described “wise guy” originalist, who believes the Constitution means today what it meant when it was first written. The other is a diplomatic former Harvard Law School dean who believes there must be “flexibility” in interpreting the nation’s governing document. Although they are often at odds with each other in written opinions, U.S. Supreme Court Justices Antonin G. Scalia and Elena Kagan were full of warm praise for each other …