If witness testimony is shown to be demonstrably unreliable, can it be stricken?
<p>If a witness makes answers that indicate the witnesses testimony is entirely unreliable, can previous assertions of fact by the witness be stricken, or is it completely up to the jury whether to believe the witness or not?</p>
<p>For example, suppose the prosecution calls a witness who testifies that he saw the defendant at a bar on a particular Wednesday night.</p>
<p>Later, the defense cross-examines the witness and asks factual questions about the bar in question and the witness makes repeated mistatements in his answers. For example, under cross examination the witness claims he &quot;parked in the bar's parking lot&quot; and it turns out the bar has no parking lot. And he says he ate dinner at the bar that night, but it turns out that the bar does not serve food during weekdays. And so on, and so forth.</p>
<p>So, in this situation, where a witness makes multiple statements that are blatantly untrue, is it grounds for the rest of their testimony be stricken as demonstrably unreliable?</p>

<h2>Whether a witness is credible is a matter of fact, whether to strike testimony is a matter of law</h2>
<p>So, in a jury trial, the decision isn’t even made by the same person: juries decide matters of fact judges decide matters of law.</p>
<p>Testimony can be stricken because it’s inadmissible under the law: it’s hearsay, or opinion (for a non-expert witness) etc. Not because the witness is obviously wrong. I won’t say lying because that’s perjury - a serious allegation that would require evidence of intent to deceive the court.</p>

united-states criminal-law testimony