Davis v. Cain, 467 P.3d 816

Petitioner (Davis) convicted of first-degree rape based on sexual intercourse with a physically helpless victim (J); DNA matched petitioner and J had little memory of the incident.
Key eyewitness was Shannon, who told police she saw J unresponsive; Officer Gilhuber documented that Shannon said J “appeared” asleep, but at trial Shannon partially recanted portions of that account.
Prosecutor’s opening statement repeatedly vouched for the truth of Shannon’s pretrial statements, saying Shannon had told the truth to police and that he would “not back off” or would “pull teeth” to get her to tell the truth if she lied at trial.
Defense counsel did not object to the prosecutor’s vouching during opening; the jury convicted petitioner.
Petitioner sought post-conviction relief claiming ineffective assistance for failure to object; the post-conviction court denied relief, but the appellate court reversed and remanded as to that first claim, finding counsel’s performance unreasonable and prejudicially likely to affect the outcome.

Issue	Davis's Argument	Cain's Argument	Held
Whether prosecutor’s opening statements constituted improper vouching for the state’s key witness	Prosecutor vouched for Shannon’s pretrial statements and invited jurors to accept his view of her credibility; counsel should have objected	Prosecutor’s remarks were permissible argument or defense strategy could benefit from the prosecution flagging potential witness inconsistency	Court: Statements were improper vouching (prosecutor advanced personal opinion and suggested superior knowledge)
Whether failure to object was objectively reasonable and prejudicial (ineffective assistance)	Failure to object was not a reasonable tactic and could have tended to affect the outcome given centrality of Shannon’s credibility	Trial counsel may have made a tactical choice or relied on jury’s lack of visible reaction; post-conviction court called the choice tactically sound	Court: Counsel’s decision not to object was objectively unreasonable and could have tended to affect the verdict; remand for relief on that claim

Montez v. Czerniak, 355 Or 1 (discusses two-step ineffective-assistance inquiry and objective-reasonableness standard)
Krummacher v. Gierloff, 290 Or 867 (Oregon right to adequate assistance under Article I, §11)
State v. Chandler, 360 Or 323 (defines prosecutorial vouching and its prohibition)
State v. Sperou, 365 Or 121 (prohibits lawyers’ personal opinions on witness credibility)
State v. Parker, 235 Or 366 (explains rule against counsel expressing personal appraisal of witness credibility)
State v. Milbradt, 305 Or 621 (witness vouching is highly prejudicial; cure by instruction may be insufficient)
Green v. Franke, 357 Or 301 (prejudice standard: could have tended to affect outcome for inadequate assistance claims)