That is so, in part, because it is not clear whether an Oregon judge is ever required to grant a mistrial sua sponte based on improper argument. Compare State v. Simonsen, 329 Or. 288, 300-01, 986 P.2d 566 (1999), with State v. Montez, 324 Or. 343, 356-57, 927 P.2d 64 (1996) ( Montez II), with State v. Montez, 309 Or. 564, 601-02, 789 P.2d 1352 (1990) ( Montez I). See generally Walton, 311 Or. at 248 n 15 ("Mistrials granted sua sponte are disfavored because of the former jeopardy problems they may create."). Montez I, 309 Or. at 601-02.

Jury argument properly may include references to matters that are within the bounds of the issues and evidence in the case. See State v. Simonsen, 329 Or. 288, 298, 986 P.2d 566 (1999), cert. den.,528 U.S. 1090, 120 S.Ct. 822, 145 L.Ed.2d 692 (2000) (where the challenged statements in the state's closing argument contained information that the state had introduced as evidence, the defendant “failed to demonstrate how those statements, which referred to evidence already before the jury, resulted in prejudice”). Assuming, without deciding, that the trial court erred by instructing the jury to disregard defense counsel's statement, we conclude that the error was harmless because counsel made substantially the same argument to the jury immediately after the court's intervention.

Consideration of the substance of petitioner's first assignment of error (pertaining to alleged ex post facto and other violations flowing from the imposition of a sentence of death based on a statutory scheme enacted after commission of the crime) is procedurally barred under Palmer v. State of Oregon, 318 Or. 352, 362, 867 P.2d 1368 (1994), both because petitioner failed to plead facts necessary to establish a basis for obtaining postconviction relief and because that claim was previously raised, and rejected, on direct review. See State v. Simonsen, 329 Or. 288, 301–02, 986 P.2d 566 (1999), cert. den., 528 U.S. 1090, 120 S.Ct. 822, 145 L.Ed.2d 692 (2000) (Simonsen III ); ORS 138.550(2). In all events, even if it were reviewable, that claim would fail on its merits.

Here, defendant describes the error that he contends is "plain" as an error by the trial court in failing to order a mistrial or issue curative instructions. See, e.g. , State v. Fanus , 336 Or. 63, 84, 79 P.3d 847 (2003) ; State v. Simonsen , 329 Or. 288, 301, 986 P.2d 566 (1999) ; State v. Montez , 324 Or. 343, 356, 927 P.2d 64 (1996) (all identifying issue as whether trial court's error in failing to act to address prosecutor's allegedly impermissible comments was plain error). If the trial court had been asked to take those actions and denied motions to do so, an appellate court would review such a denial for abuse of discretion.

Obviously, a prosecutor does not violate the foregoing rules merely by arguing at closing that the evidence shows that the defendant is guilty. See State v. Simonsen , 329 Or. 288, 298, 986 P.2d 566 (1999), cert. den. , 528 U.S. 1090, 120 S.Ct. 822, 145 L.Ed.2d 692 (2000) (where challenged statements in state's closing argument contained information that the state had introduced as evidence, the defendant "failed to demonstrate how those statements, which referred to evidence already before the jury, resulted in prejudice"); State v. Risen , 192 Or. 557, 566, 235 P.2d 764 (1951) ("Some latitude should be allowed to a prosecuting attorney in his argument in a criminal case in which there is evidence sufficient to justify a denunciation of the defendant's conduct in strong terms[.]"). Similarly, although counsel may not express personal opinions as to witnesses' credibility, counsel may argue that the jury should regard a witness as credible (or not) based on, for instance, the witness's demeanor and testimony.

Because defendant's proposed instruction was not correct as to counts 1 and 2, the trial court correctly declined to give it. See State v. Simonsen, 329 Or. 288, 297, 986 P.2d 566 (1999), cert. den., 528 U.S. 1090, 120 S.Ct. 822, 145 L.Ed.2d 692 (2000) (trial court does not err by refusing to give jury instruction that is not correct statement of law). IV. OTHER ASSIGNMENTS OF ERROR

We have only once before considered whether a remark made during voir dire by a prospective juror so tainted the entire panel as to deprive a defendant of the right to an impartial jury. In State v. Simonsen, 329 Or 288, 986 P2d 566 (1999), the defendant successfully appealed his death sentence, and the case was remanded for a new penalty-phase trial. During voir dire on remand, one of the prospective jurors stated that he had heard on the news that the defendant's earlier death sentence had been overturned.

This court consistently has held that a motion for a mistrial is addressed to the sound discretion of the trial court because the trial court is in the best position to assess and rectify any potential prejudice to the defendant. State v. Farrar, 309 Or. 132, 164, 786 P.2d 161 (1990) (so stating); see alsoState v. Simonsen, 329 Or. 288, 300, 986 P.2d 566 (1999) (same). Thus, even if the court finds that a prosecutor's statements were improper, this court will not find that a trial court's failure to grant a mistrial sua sponte constituted error apparent on the face of the record unless it was "beyond dispute that the prosecutor's comments were so prejudicial as to have denied defendant a fair trial."

" 310 Or. at 24; see also State v. Simonsen, 329 Or. 288, 300, 986 P.2d 566 (1999) cert den 528 U.S. 1090, 120 S.Ct. 822, 145 L.Ed.2d 692 (2000) (approving principle). We hold that the same standard applies to the prosecutor's alleged nonverbal conduct.

However, as this court never has addressed this issue, this court is not bound by the Court of Appeals' ruling as law of the case. See generally State v. Simonsen, 329 Or. 288, 302, 986 P.2d 566 (1999) (demonstrating that, although Supreme Court may proceed on basis of law of case as established below, it considers itself bound to do so only by former decisions of Supreme Court made in same case and on same set of facts). We originally allowed review of this case to decide whether the Court of Appeals' "comparative approach" to analysis and application of the equitable defense of unclean hands was correct.