Impeaching Witnesses in Federal and Texas Criminal Cases

Assoc. Prof. Eric Porterfield, UNT Dallas College of Law conviction is admissible is whether excluding the juvenile conviction would violate the Constitution. The quintessential example is Davis v Alaska, where the defendant should have been allowed to question the state’s identification witness about his vulnerable status as a convicted juvenile offender because it was relevant to the witness’s bias or interest in testifying for the state. 415 U.S. 308 (1974); see Bias Stemming from Pending Charges or Probationary Status, supra.

One small but significant difference between federal and Texas rule 609 is that the pendency of an appeal does not affect the admissibility in federal court but renders the conviction inadmissible in Texas state court. And the Texas rule requires the opposing party to be given written notice of intent to use a conviction under Rule 609 upon written request.

D. Capacity

A witness may be impeached with evidence that the witness suffered from some infirmity that affected the witness’s capacity. Capacity includes the witness’s ability to perceive, recall, or testify accurately about an event. The rules do not explicitly address impeachment of a witness’s capacity. This impeachment method is largely restrained by the rules of relevance, including Rule 403, and Rule 611 vesting discretion in the trial court to control the presentation of evidence to effectively determine truth, avoid wasting time, and protecting witnesses from harassment or undue embarrassment. Subject to these rules, extrinsic evidence is generally admissible because whether a witness really had the opportunity to acquire personal knowledge and is accurately conveying that personal knowledge to the jury is central to the truth-seeking function of a trial. There are many possible ways to demonstrate a witness’s defects in capacity:

• Mental illness, insanity, or mental condition. “Insane persons who, in the opinion of the court, are in an insane condition of mind at the time when they are offered as a witness, or who, in the opinion of the court, were in that condition when the events happened of which they are called to testify” are incompetent as witnesses. Tex. R. Evid. 601(a); see Fed. R. Evid. 601(a)(1). “Cross-examination of a testifying State's witness to show that the witness has suffered a recent mental illness or disturbance is proper, provided that such mental illness or disturbance is such that it might tend to reflect upon the witness’s credibility.” Virts v. State, 739 S.W. 2d 25, 30 (Tex. Crim. App. 1987).

• Alcohol or drug use by the witness. The substance use must have been used contemporaneously with the event; otherwise, the evidence is merely the witness’s propensity to use substances, which is impermissible character evidence. It is impermissible to impeach a witness with merely the fact that she is addicted to drugs. “Counsel must demonstrate an actual drug-based mental impairment during the witness’ observation of the crime in order to pursue impeachment of a witness’ perceptual capacity with evidence of drug addiction. Lagrone v. State, 942 S.W.2d 602, 613 (Tex. Crim. App. 1997). The trial court properly admitted evidence that appellant had consumed a quart of beer at lunch, because this was relevant to his mental and physical condition at the time of the baby’s death. Sandow v. State, 787 S.W. 2d 588, 598 (Tex. App. Austin 1990, pet. ref’d). Whether the defense witness was smoking marijuana was admissible to show motive and to test his ability to recollect the events in question. Albiar v. State, 705 S.W. 2d 305, 309 (Tex. App. San Antonio 1986), rev’d on other grounds, 739 S.W. 2d 360 (Tex. Crim. App. 1987).