Rosenberg v. Fleuti, 374 U.S. 449, 462 (1963). The Board relies on the interpretation of the “Fleuti doctrine” in Matter of Rangel, 15 I&N Dec. 789, 791-92 (BIA 1976), in which it was held that the correct forum to adjudicate the lawfulness of an original admission is a deportation proceeding, not an exclusion proceeding. The Board analogizes Mr. Pena’s case to that in Matter of Rangel and holds that the proper forum for the determination of his original application for adjustment of status is a deportation proceeding and not an exclusion proceeding.