If a statement is assertive -- that is, if the declarant's statement does assert that some matter is true -- the statement is nevertheless non-hearsay if the statement is offered to prove that some matter other than the asserted matter is true.

Old Chief v. United States, 519 U.S. 172, pin? (1997).Evidence that is relevant to a material fact is relevant for purposes of Federal Rule of Evidence 401 and the federal law of evidence even though the material fact is undisputed.

Rock v. Arkansas, 483 U.S. 44, pin? (1987) (a per se rule that makes relevant testimony by previously-hypnotized criminal defendant inadmissible is unconstitutional; the reach of this decision was later....If the testimony that a criminal defendant offers to give is relevant to the defendant's guilt or innocence, it is a violation of the United States Constitution for the trial court to prevent the defendant from testifying because the defendant was previously hypnotized.

Hudson v. Michigan, 547 U.S. 586, 626 (2006) (inevitable discovery exception to Forth Amendment-based exclusionary rule; Court quotes with approval Nix v. Williams, 467 U.S. 431, at 444 (1984): ?If the prosecution can establish by a preponderance of the evidence that the information ultimately or...The government can have the burden of proof on factual issues other than the essential elements of the crime charged and the government's burden of persuasion on such "collateral" issues can be and often is less than proof beyond a reasonable doubt. Conversely, sometimes a criminal defendant rather than the government has the burden of proof and persuasion with respect to factual issues that arise under legal rules and requirements apart from the essential elements of the crime charged; for example, a defendant may have the burden of establishing a defense such as duress.