Res Judicata is a common law doctrine which prevents a party from relitigating a matter which has already been decided by another court of competent jurisdiction. Res judicata takes two distinct forms: issue estoppel and cause of action estoppel. In brief terms, issue estoppel prevents a litigant from raising an issue that has already been decided in a previous proceeding. Cause of action estoppel prevents a litigant from pursuing a matter that was or should have been the subject of a previous proceeding. If the technical requirements of issue estoppel or cause of action estoppel are not met, it may be possible to invoke the doctrine of abuse of process to prevent relitigation of matters.
In Toronto (City) v. C.U.P.E., Local 79 2—3 SCC 63 , the Supreme Court of Canada described issue estoppel as a doctrine which precludes the relitigation of issues previously decided in court in another proceeding. For issue estoppel to be successfully invoked, three preconditions must be met:
- the issue must be the same as the one decided in the prior decision;
- the prior judicial decision must have been final; and
- the parties to both proceedings must be the same, or their privies.
With respect to the final requirement, known as mutuality, the SCC noted it has been largely abandoned in the United States and has been the subject of much judicial and academic debate in the UK and Canada. Despite careful consideration of the aforementioned debate, the court concluded that there was no need to reverse or relax the long standing application of the mutuality requirement.
Cause of Action Estoppel
In Erschbamer v. Wallster, 2013 BCCA 76., The Court of Appeal for British Columbia reviewed the two aspects of the doctrine of res judicata. The court noted that in brief terms, cause of action estoppel prevents a litigant from pursuing a matter that was or should have been the subject of a previous proceeding. If the technical requirements of issue estoppel or cause of action estoppel are not met, it may be possible to invoke the doctrine of abuse of process to prevent relitigation of matters. With respect to cause of action estoppel, the court in Erschbamer referenced the seminal case of Henderson v. Henderson (1843), 3 Hare 100, 67 E.R. 313 at 319:
The BCCA in Erschbamer revisited its analysis of the requirements of both issue estoppel and cause of action estoppel in Cliffs Over Maple Bay Investments Ltd. (Re), 2011 BCCA 180. In Cliffs Over Maple Bay, Madam Justice Newbury set out the requirements of cause of action estoppel at para. 28:
- There must be a final decision of a court of competent jurisdiction in the prior action [the requirement of “finality”];
- The parties to the subsequent litigation must have been parties to or in privy with the parties to the prior action [the requirement of “mutuality”];
- The cause of action in the prior action must not be separate and distinct; and
- The basis of the cause of action and the subsequent action was argued or could have been argued in the prior action if the parties had exercised reasonable diligence.
Although it is referred to as cause of action estoppel, the principle applies to defences as well as claims. This is explained in Donald J. Lange, The Doctrine of Res Judicata in Canada, 3d ed. (Markham, Ontario: LexisNexis, 2010) at 137-38: While the plaintiff may not split a cause of action or pursue litigation by instalments, the defendant may not split the defence by turning around and, as the plaintiff in a subsequent action, sue on an issue which, if successful, would challenge the integrity of the previous judgment. In other words, a cause of action in a second action which could have been a defence in the first action, but was not raised, is barred… The cloak of cause of action estoppel is woven the same for both the plaintiff and the defendant in subsequent proceedings.
Abuse of Process
Judges have an inherent and residual discretion to prevent an abuse of the court’s process. This concept of abuse of process was described at common law as proceedings “unfair to the point that they are contrary to the interest of justice” (R. v. Power, 1994 CanLII 126 (SCC),  1 S.C.R. 601, at p. 616), and as “oppressive treatment” : R. v. Conway, 1989 CanLII 66 (SCC),  1 S.C.R. 1659, at p. 1667. In Canada, the common law doctrine of abuse of process is subsumed into the principles of the Canadian Charter of Rights and Freedoms such that there is often overlap between abuse of process and constitutional remedies (R. v. O’Connor,  4 SCR 411). The doctrine nonetheless continues to have application as a non-charter remedy: United States of America v. Shulman,  1 S.C.R. at para 33. In Canam Enterprises Inc. v. Coles,  3 SCR 307, the SCC agreed with Goudge J.A.’s dissenting opinion in the Ontario Court of Appeal. Goudge J.A. noted that the doctrine of abuse of process engages “the inherent power of the court to prevent the misuse of its procedure, in a way that would….. bring the administration of justice into disrepute.” The doctrine was further expanded upon at paragraphs 55 to 56: The doctrine of abuse of process engages the inherent power of the court to prevent the misuse of its procedure, in a way that would be manifestly unfair to a party to the litigation before it or would in some other way bring the administration of justice into disrepute. It is a flexible doctrine unencumbered by the specific requirements of concepts such as issue estoppel. See House of Spring Gardens Ltd. v. Waite,  3 W.L.R. 347 at p. 358,  2 All E.R. 990 (C.A.). One circumstance in which abuse of process has been applied is where the litigation before the court is found to be in essence an attempt to relitigate a claim which the court has already determined. Although it has largely given way to arguments framed around the constitutional guarantees of the Canadian Charter of Rights and Freedoms, the common law doctrine of abuse of process remains a route to obtaining a remedy where the facts before the court do not fit neatly into the specific requirements associated with the doctrine of res judicata.