There is a privilege for congressional speech or debate

Sims v. Great American Life Ins. Co., 469 F.3d 870, 881-882 (10th Cir. 2006) (in the course of a discussion of whether some Federal Rules of Evidence violate the Erie doctrine in certain kinds of civil cases, the court of appeals said, "Most pertinent to this case, Rule 401 protects against incursion...The technical definition of relevance in Federal Rule of Evidence 401 and in comparable State rules provides that evidence is "relevant" only if the evidence increases or decreases the probability of a fact that is "of consequence to the determination of the action."

Holmes v. South Carolina, 547 U.S. 319, pin? (2006).The Due Process and Compulsory Process guarantees give a defendant in a federal or state criminal trial the constitutional right, not only to compel the attendance of defense witnesses, but also to introduce trustworthy hearsay evidence that is critical or important to the defendant's defense.

United States v. Troutman, 814 F.2d 1428, 1455 (10th Cir. 1987) (upholding trial court's exclusion of testimony about accused's past official conduct in matters unrelated to ITC because "extortion or refraining from extortion is not a semi-automatic act and does not constitute habit." ).If behavior is largely volitional rather than semi-volitional or semi-automatic, it is hot habit.