A criminal defendant has a federal constitutional right, grounded principally in the Fifth Amendment Privilege against Self-Incrimination, to testify at his or her trial in his or her own defense if the defendant has any relevant testimony to give about his or her guilt or innocence.

United States v. Diggs, 649 F.2d 731, 737 (9th Cir. 1981) (upholding trial court's refusal to exclude witness's testimony about unrecovered bank deposits totalling $16,500 because when accused raised entrapment as a defense, the prosecution may introduce evidence to show his criminal propensity and...A subjective entrapment defense makes an accused's criminal liability contingent on a finding of the accused's predisposition or the accused's lack of predisposition to commit the crime charged and since criminal predisposition is a character trait, the defense of subjective entrapment makes accused's character an element of either a defense or a criminal charge, evidence of accused's criminal predisposition -- including evidence in the form of reputation, opinion, and evidence of specific instances of accused's conduct -- is not barred by the rule against the use of a person's character to show the person's conduct.

Fed. R. Evid. 403 ("Although relevant, evidence may be excluded if its probative value is substantially outweighed ... by considerations of undue delay, waste of time").The trial court may use Federal Rule of Evidence 403 to exclude relevant evidence if the court finds that the probative value of the evidence is substantially outweighed by considerations of undue delay, waste of time, or waste of resources.

Cf. United States v. Zedner, 401 F.3d 36, 49-50 (2d Cir. 2005) (upholding trial court's admission into evidence of rebuttal witnneses' testimony about accused's previous commission of fraud, where accused claimed lack of criminal intent, and evidence of fraud was relevant to prove accused's...Evidence of another crime, wrong, or act is not barred by the prohibition against circumstantial use of character if such other crime, wrong, or act is offered to prove the existence of a plan or scheme.