Barrister and Solicitor
Legal Writing and Research
Dagg v. Cameron Estate (Ont CA, 2017)
Here the Court of Appeal summarizes the law of mootness, being the issue of when and whether a court should continue to decide a case despite the fact that the cause of action (lis) between the parties has otherwise been resolved:
 Where, as here, the dispute between the parties has disappeared, the court still retains the discretion to proceed to hear the merits of the appeal: Borowski v. Attorney General for Canada, 1989 CanLII 123 (SCC),  1 S.C.R. 342, at p. 353.
 The exercise of that discretion is guided by a consideration of the presence or absence of the three rationales underpinning the mootness doctrine: (i) whether the issues can be well and fully argued by parties who have a stake in the outcome; (ii) the concern for judicial economy; and (iii) the need for the court to remain alive to the proper limits of its law-making function in order to avoid intrusions into the role of the legislative branch: Borowski, at pp. 358-63; Ontario Provincial Police Commissioner v. Mosher, 2015 ONCA 722 (CanLII), 330 C.C.C. (3d) 149, at paras. 31-32. The interplay amongst the three rationales was described in Borowski at p. 363:
In exercising its discretion in an appeal which is moot, the Court should consider the extent to which each of the three basic rationalia for enforcement of the mootness doctrine is present. This is not to suggest that it is a mechanical process. The principles identified above may not all support the same conclusion. The presence of one or two of the factors may be overborne by the absence of the third, and vice versa.