Whether a party is permitted to impeach its own witness with a prior inconsistent statement and, if so, the circumstances under which such impeachment is permissible

United States v. Tail, 459 F.3d 854, 859 (8th Cir. 2006) (upholding trial court's exclusion of evidence of the victims' sexual histories because such evidence showed victims' past sexual behavior or conduct).Rape shield laws frequently make it impermissible -- sometimes in trials of civil actions as well as in criminal trials -- to introduce evidence either to show that an alleged victim of sexual wrongdoing engaged in other sexual behavior or to show the alleged victim's sexual predisposition.

Fed. R. Evid. 406 advisory committee's note ("An oft-quoted paragraph, McCormick, Section 162, p. 340, describes habit in terms effectively contrasting it with character: 'Character and habit are close akin. Character is a generalized description of one's disposition, or of one's disposition in respect to a general trait, such as honesty,...Habit is a regular response to a specific situation.

Union Mutual Life Insurance Co. v. Chrysler Corp., 793 F.2d 1, 8-9 (1st Cir. 1986) (holding, in plaintiff lending company's action against defendants computer leasing company and another lessee company for breach of lease agreement, that the....A statement is imputed to a principal or to an employer and is treated as the principal's or employer's vicarious admission (which, like other admissions is exempt from the hearsay rule) if the principal or employer is a party, the statement is offered against the principal or party, the statement is a statement by the party's agent or employee about a matter within the scope of the agent's agency or the employee's employment, and the statement is made during the principal-agent or employer-employee relationship.