Criminal - Mistrial. R. v. Cummins
In R. v. Cummins (Ont CA, 2023) the Court of Appeal considered CCC s.653.1, regarding rulings made in a mistrial that may be preserved in a subsequent trial:
 The appellant’s third trial proceeded. After the Crown’s case was completed, the appellant asked the trial judge to prohibit the Crown from referring to the cross-examination in the first trial. The trial judge ruled that the Crown could make use of the appellant’s testimony and dismissed the application. The trial judge’s ruling made it clear that he did not agree with Forestell J.’s decision to declare a mistrial and referred to s. 653.1 of the Criminal Code, which provides:. R. v. Collins
In the case of a mistrial, unless the court is satisfied that it would not be in the interests of justice, rulings relating to the disclosure or admissibility of evidence or the Canadian Charter of Rights and Freedoms that were made during the trial are binding on the parties in any new trial if the rulings are made — or could have been made — before the stage at which the evidence on the merits is presented. The appellant submits that the trial judge erred because the evidence in question only came about as the result of the Crown’s misconduct. He argues that the ruling by Forestell J. was binding on the trial judge by virtue of “judicial comity” and that s. 653.1 was not engaged. He submits that this error so affected the trial that the appeal should be allowed, and a new trial ordered.
 We do not accept these submissions.
 Judicial comity might suggest that the trial judge should not have indicated disagreement with the mistrial ruling. However, the decision about use of the transcript was a discretionary decision to be made by the trial judge. The trial judge explained his reasons at para. 22 of his ruling:
In deciding whether or not to testify, Mr. Cummins was in a position to know the case he would have to meet, including the potential of being confronted with what he said at his first trial, if what he said in this trial were to differ. If he were to have testified in a manner inconsistent with something he earlier said, it would not have been unfair, in my view, to permit the Crown to confront the applicant with his earlier testimony. I say that bearing in mind that the Supreme Court of Canada has made plain that “[a]ccused persons who testify at their first trial and then volunteer inconsistent testimony at the re-trial on the same charge are in no need of protection ‘from being indirectly compelled to incriminate themselves’ in any relevant sense of the word and s. 13 protection should not be available to them.” [Citations omitted] The evidence did not come about because of the Crown’s misconduct. The misconduct identified by Forestell J. was case splitting. Although the video clips had been disclosed by the Crown in the usual way, they had not formed part of the Crown’s case. The trial judge determined that the proper remedy was a mistrial. We agree that s. 653.1 is not engaged. The ruling of Forestell J. did not concern disclosure, admissibility, or a Charter ruling. The appropriate use of the transcript was not at issue. But, even if s. 653.1 did apply, the opening words of the section provide “unless the court is satisfied that it would not be in the interests of justice.”
 We see no reason to interfere with the trial judge’s discretionary decision to allow the cross-examination.
In R. v. Collins (Ont CA, 2023) the Court of Appeal considered an appeal from murder and an attempted murder convictions. In this quote to court considers the trial judge's role in ordering a mistrial:
 A mistrial is a discretionary remedy of last resort, and the trial judge is ideally situated to make the assessment of whether a lesser remedy will be efficacious in addressing any prejudice that arises at trial: see R. v. Khan, 2001 SCC 86 (CanLII),  3 S.C.R. 823, at para. 36; R. v. Jeanvenne, 2010 ONCA 706, 261 C.C.C. (3d) 462, at para. 58; and R. v. Anderson, 2018 ONCA 1002, at para. 15.. R. v. Donnelly
 The appellant places great weight on R. v. Pierre,  B.C.J. No. 2849 (B.C.S.C.). Pierre was charged with sexual offences against young boys. He was convicted at trial, but the Court of Appeal ordered a new trial. On the evening before Pierre was to open his case, media coverage revealed that this was a re-trial of a case in which the accused had been found guilty at his first trial. The coverage also mentioned that there had been a change of venue for the re-trial because of expressed concern about prejudicial publicity in the original jurisdiction. After reviewing many authorities, the trial judge, Cohen J., held that he was not convinced that a caution to the jury could cure the prejudice created by the media coverage. He declared a mistrial.
 The appellant submits that the trial judge should have placed more weight on Pierre in his mistrial ruling. The trial judge considered Pierre. But mistrial applications are very fact-specific, based on the nature of the triggering events, all within the dynamics of the trial in which they occur. This is why mistrial rulings of fellow trial judges will often be of limited value to a trial judge exercising their discretion in deciding whether to grant a mistrial.
 The trial judge’s ruling was well-reasoned. He subsequently did what he said he would do, and that was to provide strong warnings to the jury to ignore what may or may not have happened at the previous trial. I see no error. In my view, the trial judge restored trial fairness in the steps that he took in a very timely manner.
In R. v. Donnelly (Ont CA, 2023) the Court of Appeal considered the degree of trial error required before a mistrial will be declared:
 It is well established that a mistrial is the remedy of last resort that should only be declared in the clearest of cases and where no remedy short of that relief will adequately redress the actual harm occasioned. The applicant bears the burden of demonstrating on a balance of probabilities that the right to make full answer and defence has been violated: R. v. Barra, 2021 ONCA 568, 157 O.R. (3d) 196, at paras. 138, 147; R. v. Bjelland, 2009 SCC 38,  2 S.C.R. 651, at paras. 20-21, 23.
 The court must consider whether other less drastic steps could remediate the issues that threaten trial fairness. The decision of whether to declare a mistrial falls within the discretion of the trial judge, who must assess whether there is a real danger that trial fairness has been compromised. Although the discretion is not absolute, the corrective measure chosen by the judge is subject to appellate deference: see e.g., R. v. Khan, 2001 SCC 86,  3 S.C.R. 823, at paras. 79-80; R. v. Toutissani, 2007 ONCA 773, at para. 9; R. v. Chiasson, 2009 ONCA 789, 258 O.A.C. 50, at para. 14. Appellate intervention is warranted only where there is material misdirection or the decision is so clearly wrong that an injustice has occurred: Bjelland, at para. 15.