((a)) ** .—** Jurisdiction of the United States with respect to a vessel subject to this chapter is not an element of an offense. Jurisdictional issues arising under this chapter are preliminary questions of law to be determined solely by the trial judge.

((b)) ** .—** A person violating section 70503 or 70508—

((1)) shall be tried in the district in which such offense was committed; or

((2)) if the offense was begun or committed upon the high seas, or elsewhere outside the jurisdiction of any particular State or district, may be tried in any district.