search for the truth and are therefore generally disfavored. Trammel v. Unked States, 445 U.S. 40, 50. 100 S.Ct. 906, 912, 63 L.Ed.2d 186 (1980); Herbert v, Lando, 441 U.S. 153. 99 S.Ct. 1635, 60 L.Ed.2d 115 (1979); United Stares v. Nixon, 418 U.S. 683, 709-10, 94 5.O. 3090, 3108- 09, 41 L.Ed.24 1039