Prosecuitorial Misconduct

Excerpted from: Prosecutorial Misconduct, 40 Georgetown Law Journal Annual Review of Criminal Procedure 628 (2011) (45 footnotes Omitted)

The prosecutor's duty in a criminal prosecution is to seek justice. Therefore, the prosecutor should “prosecute with earnestness and vigor,” but may not use “improper methods calculated to produce a wrongful conviction.” Prosecutorial misconduct justifies declaring a mistrial where it “so infect[s] the trial with unfairness as to make the resulting conviction a denial of due process.” A claim of prosecutorialmisconduct requires proof of improper conduct by the prosecutor that, taken in the context of the trial as a whole, violated the defendant's due process rights.

Improper Conduct. Courts review de novo whether a challenged statement by a prosecutor is improper. Although the line between proper and improper advocacy is not always clear, courts have consistently found certain types of prosecutorial conduct improper. A prosecutor may not elicit information from a defendant outside the presence of the defendant's counsel. A prosecutor may not express personal opinions about the defendant's guilt or credibility, and must avoid making potentiallyunfair or improper remarks about the defendant, defense counsel, or a defense witness. Nor may the prosecutor express opinions about matters requiring personal experience or expert knowledge. The prosecutor may not comment on the defendant's failure to testify at trial and, with certain exceptions, may not refer to previous convictions, current guilty pleas, or other bad acts of the defendant, codefendants, or coconspirators. The prosecutor may not vouch for the credibility of government witnesses or allude to his or her own personal integrity or oath of office to bolster the government's case. In addition, “[i] t is an almost universally frowned upon practice for a prosecutor to testify at the trial of the case” he or she is prosecuting. The prosecutor may not appeal to jurors to act as a conscience for the community or make other remarks likely to inflame the passions of the jurors if the remarks are intended to lead to conviction for an improper reason.

The prosecutor may not prosecute a defendant for vindictive reasons. In addition, the prosecutor may not knowingly present false testimony and has a duty to correct testimony that he or she knows to be false. Further, the prosecutor must disclose evidence favorable to the defendant if the defendant so requests. Although inconsistent testimony by a government witness is usually not improper, a prosecutor may not use staged testimony to attempt to introduce inadmissible evidence.

The prosecutor may not make material misstatements of law or fact. A prosecutor must confine his or her opening statement to evidence that he or she intends to offer and believes will be admissible. The prosecutor must similarly limit his or her trial statements and closing argument to evidence that has been admitted into the record and permissible inferences therefrom. A prosecutor may not use a defendant's post-arrest, post-Miranda silence for impeachment purposes, because the Miranda warnings implicitly assure a defendant that he or she will not be penalized for remaining silent. Nonetheless, a prosecutor may impeach a testifyingdefendant with prearrest silence or post-arrest, pre-Miranda silence, because the defendant could not have relied on Miranda's implicit assurance. It is improper for a prosecutor to question a third-party witness knowing the witness will reply by validly invoking his or her Fifth Amendment privilege against self-incrimination, because the jury might improperly infer guilt from the witness's silence. The prosecutor may not suggest that the defendant's retention of counsel indicates guilt.

Appellate Review. Although appellate courts review the propriety of prosecutorial conduct de novo, they usually defer to the trial judge's conclusions about the effects of prosecutorial misconduct on trial fairness. To preserve a claim of improper conduct by the prosecutor for appeal, the defendant generally must make a timely objection. Even where the objection is timely, prosecutorial misconduct is subject to harmless error review, under which courts consider a variety of factors to evaluate whether the alleged misconduct prejudiced the defendant. If, however, a timely objection is not made, an appellate court will reverse the conviction only if the lower court's allowance of the prosecutor's conduct constituted plain error that both impaired the defendant's rights and harmed the integrity of the proceedings. Habeas corpus relief for trial errors involving prosecutorial misconduct will be granted only if the error “‘had substantial and injurious effect or influence in determining the jury's verdict”’ or otherwise “infect[ed] the integrity of the proceeding.”

Appellate courts consider a number of factors in evaluating the seriousness of misconduct, including whether the prosecutor's misconduct was deliberate or accidental, the degree to which the prosecutor's conduct may have prejudiced the defendant, the effect of curative instructions to the jury, and whether the weight of the evidence made conviction certain absent the improper conduct. Courts generally do not reverse convictions when a prosecutor's misconduct was “invited” by arguments advanced by the defendant.