The idea of accepting a pardon means an admission of guilt is still debated by many law historians. According to Associate Justice Joseph McKenna, writing the majority opinion in the U.S. Supreme Court case Burdick v. United States, a pardon "carries an imputation of guilt; acceptance a confession of it." Associate Justice McKenna was referring to cases in the denial of a pardon. His comment was not intended for all pardons. Also, the federal courts have yet to make it clear how this logic applies to persons who are deceased (such as Henry Ossian Flipper, who was pardoned by Bill Clinton), those who are relieved from penalties as a result of general amnesties, and those whose punishments are relieved via a commutation of sentence (which cannot be rejected in any sense of the language). Brian Kalt, a law professor at Michigan State University, claims that presidents usually grant a pardon to someone on the basis that the person is innocent. If a president thinks an individual is innocent and issues a pardon, then accepting a pardon would not mean the individual is guilty.