State v. Marquez-Vela, 338 P.3d 813

Defendant stabbed neighbor Graham after an altercation; Graham died and defendant fled to Mexico, later surrendering three years later.
At trial defendant raised voluntary intoxication (claimed he had "blanked out" and was too drunk to form intent).
Detective Ober conducted a post-arrest interrogation and testified at trial about defendant’s demeanor and statements.
On redirect, Ober testified that defendant “was dishonest,” “untruthful,” “lying,” and was “selectively leaving out details”; the trial court allowed these credibility statements despite defense objections.
Defendant did not testify; prosecution used the interrogation to argue defendant remembered selectively and therefore had intent.
Defendant appeals, arguing the court erred in admitting the detective’s comments on credibility and that the error was not harmless; the appellate court reverses conviction on Count 1 and remands for resentencing.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Admissibility of detective's comments on defendant's credibility	State: Detective's statements were proper rebuttal on redirect because defense cross suggested nonchalance was a coping mechanism, thereby "opening the door."	Defendant: Ober's statements directly commented on credibility and were inadmissible under Middleton and progeny; cross did not open the door to credibility opinions.	Court: Admission was legal error; cross-examination about demeanor did not open the door to credibility opinions.
Harmless-error analysis	State: Error was harmless because the detective's view merely restated what was obvious and defendant did not testify so his credibility "was not directly at issue."	Defendant: The improper credibility testimony undermined the central issue (whether intoxication prevented intent) and likely affected the verdict.	Court: Error was not harmless; testimony related to central issue (intent) and could have colored the jury's assessment.

State v. Middleton, 294 Or. 427 (1983) (witness may not testify whether another is truthful; credibility for trier of fact)
State v. Milbradt, 305 Or. 621 (1988) (emphasizing rule that credibility assessment is for jury; judges should cut off vouching)
State v. Lupoli, 348 Or. 346 (2010) (statements short of overt vouching may still impermissibly comment on credibility)
State v. Lowell, 249 Or. App. 364 (2012) (detective’s comments on defendant’s honesty were erroneous to admit)
State v. Watts, 259 Or. App. 560 (2013) (improper comment on credibility often prejudicial and warrants reversal)