Estoppel - Res Judicata
Canada (Attorney General) v Confédération des syndicats nationaux (SCC, 2014)
In this case, the Supreme Court of Canada briefly considered the doctrine of stare decisis, partly in contrast with the doctrine of res judicata:
 Of course, the doctrine of stare decisis is no longer completely inflexible. As the Court noted in Bedford, the precedential value of a judgment may be questioned “if new legal issues are raised as a consequence of significant developments in the law, or if there is a change in the circumstances or evidence that fundamentally shifts the parameters of the debate” (para. 42). Where, on the other hand, the legal issue remains the same and arises in a similar context, the precedent still represents the law and must be followed by the courts (Bedford, at para. 46).
 Although relatively uncommon in Quebec civil procedure, the mechanism for dismissing actions at a preliminary stage on the basis of stare decisis is similar to the res judicata exception (art. 165(1) C.C.P.). Under both of them, the legal issues raised by the applicant must already have been clearly resolved by the courts. However, unlike res judicata, stare decisis does not necessarily require that the dispute be between the same parties. What must be established is that the issue is the same and that the questions it raises have already been answered by a higher court whose judgment has the authority of res judicata.
 In Canada v. Imperial Tobacco, Gascon J.A., as he then was, explained this as follows:
[translation] In this context, the manufacturers’ argument that this case is not res judicata, because Imperial was not decided by a court of competent civil law jurisdiction or because strict identity of parties, cause and object is not established, does not appear to me to be determinative. I see no need for further discussion of the distinctions the manufacturers raise with respect to these identities of parties, cause and object, which in their view refute the AGC’s res judicata argument. In my opinion, the appropriate principle to apply to resolve the issue is instead stare decisis.......
The Superior Court should have held on the basis of stare decisis that it was bound by Imperial. The Supreme Court, by ruling as it did on the issue of the AGC’s immunity in relation to the course or principle of action challenged by the manufacturers, had in a sense barred the manufacturers’ actions in warranty by rendering them unfounded in law, even if the alleged facts were assumed to be true.
Stare decisis is a less stringent basis for an argument than res judicata, since it requires only a similar or analogous factual framework. Stare decisis is a principle “under which a court must follow earlier judicial decisions when the same points arise again in litigation” [Black’s Law Dictionary (9th ed. 2009), at p. 1537]. It applies, of course, to decisions of the Supreme Court, particularly in the area of public law as here, where the parties were involved in earlier litigation on the specific question at issue. [Emphasis added; paras. 125‑27.]
 In our opinion, it is clear that the unions’ action has no reasonable chance of success. On the basis of stare decisis, it is apparent that their main argument that the Consolidated Revenue Fund was indebted to the Employment Insurance Account is unfounded, and this conclusion dictates the outcome of the case. As a result, this Court’s decision in CSN v. Canada provides a complete, certain and final solution to the entire dispute that the unions are trying to revive. Their action was therefore properly dismissed by Perrault J. under art. 165(4) C.C.P.