Propensity, or character, is admissible if character is an essential element of a claim, charge, or defense.

Rock v. Arkansas, 483 U.S. 44, pin? (1987).The exclusion of exculpatory evidence in a criminal trial does not violate the due constitutional right to present a defense if the grounds for exclusion are not arbitrary or disproportionate.

Fed. R. Evid. 404(a)(2) ("In a criminal case, and subject to the limitations imposed by Rule 412, evidence of a pertinent trait of character of the alleged victim of the crime offered by an accused" is admissible.).In a criminal trial accused may offer a pertinent character trait of a victim to show the victim's conduct on a particular occasion; i.e., accused may use victim's character "circumstantially," as "circumstantial" evidence of victim's conduct on a specific occasion.

United States v. Garcia, 897 F.2d 1413, 1420 (7th Cir. 1990) (upholding trial court's admission of defendant's statements as statements against penal interest because (1) "[defendant] Carlos' statements implicating....A statement that exposes a declarant (other than the defendant) to criminal liability is admissible under the hearsay exception for statements against interest to exculpate a criminal defendant only if corroborating circumstances show that the statement is trustworthy.