State v. Partain, 444 P.3d 1136

Defendant was convicted of second-degree theft for leaving a Walmart with an air mattress, tent, and a backpack apparently full of smaller items shown on surveillance video.
Walmart loss-prevention officer reviewed surveillance and sales records, found no purchases for the large items during defendant’s stay, and provided video/stills to police.
Officer Kopp identified defendant from the footage, interviewed him in jail; defendant admitted being the person in the video but said he had receipts for the items and would produce them in court.
Defendant testified he shopped over a four-hour period, paid for items at various registers/self-checkout, packed receipts in the bags, and rushed out because his ride arrived; he also said he heard someone call “he’s stealing” but thought they meant someone else.
On redirect, defense counsel asked whether an implication could be made that defendant would lie because probation revocation consequences exist; the prosecutor objected when defendant tried to assert his own veracity and the court sustained the objection, preventing defendant from vouching for his testimony.
The state concedes the exclusion of defendant’s self-vouching testimony was error under Sanchez-Jacobo; the sole appellate question is whether that error was harmless.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether trial court erred by preventing defendant from vouching for his own testimony	State: exclusion of self-vouching is improper under Sanchez-Jacobo (state concedes error)	Defendant: should have been allowed to assert he was not lying when asked	Error conceded; court accepts it was erroneous
Whether the error was harmless	State: excluded assertion added nothing beyond oath and video/sales evidence dominates	Defendant: credibility was central; bar on saying “I’m not lying” likely affected verdict	Error was harmless; conviction affirmed

State v. Sanchez-Jacobo, 250 Or. App. 621 (2012) (self-vouching by a witness is not categorically barred)
State v. Davis, 336 Or. 19 (2003) (harmless-error standard: affirm if little likelihood error affected verdict)
State v. Henley, 363 Or. 284 (2018) (improperly admitted testimony may affect verdict when prosecutor relies on it in closing)
State v. Wirfs, 250 Or. App. 269 (2012) (offer of proof rules and when error can be preserved without explicit offer)
State v. Maiden, 222 Or. App. 9 (2008) (assessing nature of evidentiary error by comparing excluded evidence to admitted evidence)