In United States v. Jackson (1968) 390 U.S. 570, the high court held the penalty provisions of the federal kidnaping act unconstitutional because they authorized the imposition of the death penalty only following a jury trial. According to the court these provisions discouraged the assertion by a defendant of his Fifth Amendment right to plead not guilty and deterred the exercise of his Sixth Amendment right to demand a jury trial. The constitutional infirmity of these provisions lay, thus, in their needless encouragement of guilty pleas and jury waivers. ( Id. at pp. 581-583.)