R. v. M.T., 2013 ONCA 476:
 Helpful summaries of the doctrine of abuse of process are found in the recent decisions of R. v. Nixon, 2011 SCC 34, 2 S.C.R. 566 and R. v. Regan, 2002 SCC 12, 1 S.C.R. 297. Those cases identify two categories of abuse of process. The first, and more common, category is engaged by prosecutorial conduct affecting the fairness of the trial; the second, the residual category, is engaged by prosecutorial conduct that contravenes fundamental notions of justice and undermines the integrity of the judicial process: see Nixon at para. 36.
 In Regan, the Supreme Court explained that either category of abuse of process requires two criteria to be satisfied before a stay can be imposed. First, the applicant must show that the prejudice caused by the abuse will be perpetuated by a trial or by its outcome, and second, he must show that no other remedy is reasonably capable of removing that prejudice. The court explained the rationale for these requirements in the following way, at paras. 54-56:
The Court's judgment in Tobiass, at para. 91, emphasized that the first criterion is critically important. It reflects the fact that a stay of proceedings is a prospective rather than a retroactive remedy. A stay of proceedings does not merely redress a past wrong. It aims to prevent the perpetuation of a wrong that, if left alone, will continue to trouble the parties and the community as a whole, in the future.
As discussed above, most cases of abuse of process will cause prejudice by rendering the trial unfair. Under s. 7 of the Charter, however, a small residual category of abusive action exists which does not affect trial fairness, but still undermines the fundamental justice of the system (O'Connor, at para. 73). Yet even in these cases, the important prospective nature of the stay as a remedy must still be satisfied: "[t]he mere fact that the state has treated an individual shabbily in the past is not enough to warrant a stay of proceedings" (Tobiass, at para. 91). When dealing with an abuse which falls into the residual category, generally speaking, a stay of proceedings is only appropriate when the abuse is likely to continue or be carried forward. Only in "exceptional", "relatively very rare" cases will the past misconduct be "so egregious that the mere fact of going forward in the light of it will be offensive" (Tobiass, at para. 91).
Any likelihood of abuse which will continue to manifest itself if the proceedings continue then must be considered in relation to possible remedies less drastic than a stay. Once it is determined that the abuse will continue to plague the judicial process, and that no remedy other than a stay can rectify the problem, a judge may exercise her or his discretion to grant a stay.
 The Regan court, at para. 57, also instructed that close cases may engage a third criterion:
[T]here may still be cases where uncertainty persists about whether the abuse is sufficient to warrant the drastic remedy of a stay. In such cases, a third criterion is considered. This is the stage where a traditional balancing of interests is done: "it will be appropriate to balance the interests that would be served by the granting of a stay of proceedings against the interest that society has in having a final decision on the merits". In these cases, "an egregious act of misconduct could [never] be overtaken by some passing public concern [although] ... a compelling societal interest in having a full hearing could tip the scales in favour of proceeding" (Tobiass, at para. 92).
 More recently, the Supreme Court of Canada in Nixon suggested that the balancing of interests is a central concern that defines the concept of abuse of process and its remedy. The court reached back to R. v. Conway, and pointed out that the Conway court, at p. 1667, summarized both abuse of process and the remedy for it in these terms:
[W]here the affront to fair play and decency is disproportionate to the societal interest in the effective prosecution of criminal cases, then the administration of justice is best served by staying the proceedings.
The centrality of a balancing exercise is evident in this description. In addition, this court in R. v. Zarinchang, 2010 ONCA 286, 99 O.R. (3d) 721, at para. 58, held that where it is the residual category that is engaged, a court will generally find it necessary to balance the interests called for by the third criterion.