The following excerpt is from United States v. Flores, 802 F.3d 1028 (9th Cir. 2015):
the form of vouching; how much the vouching implies that the prosecutor has extra-record knowledge of or the capacity to monitor the witness's truthfulness; any inference that the court is monitoring the witness's veracity; the degree of personal opinion asserted; the timing of the vouching; the extent to which the witness's credibility was attacked; the specificity and timing of a curative instruction; the importance of the witness's testimony and the vouching to the case overall.
Id. at 1085; see also United States v. Williams, 989 F.2d 1061, 1072 (9th Cir.1993). Considering these factors, we conclude that the government's vouching did not substantially prejudice Flores.
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