Abuse of Process
Winter v. Sherman Estate (Ont CA, 2018)
Here the Court of Appeal considers the doctrine of abuse of process in the context of res judicata and issue estoppel:
 Further, the appellants too narrowly construe the doctrine of abuse of process. This doctrine is flexible and unencumbered by the specific requirements of res judicata or issue estoppel: Behn v. Moulton Contracting Ltd., 2013 SCC 26 (CanLII),  2 S.C.R. 227, at para 40; Toronto (City) v. C.U.P.E., Local 79, 2003 SCC 63 (CanLII),  3 S.C.R. 77, at para. 42. Where a precondition for issue estoppel has not been met, such as mutuality of parties, courts have turned to the doctrine of abuse of process to preclude re-litigation of the same issue: C.U.P.E., at para. 37. While the doctrine is similar to issue estoppel in that it can bar litigation of legal and factual issues “that are necessarily bound up with the determination of” an issue in the prior proceeding, abuse of process also applies where issues “could have been determined”: Danyluk v. Ainsworth Technologies Inc., 2001 SCC 44 (CanLII),  2 S.C.R. 460, at para. 54; Aba-Alkhail v. University of Ottawa, 2013 ONCA 633 (CanLII), 363 D.L.R. (4th) 470, at para. 13; McQuillan v. Native Inter-Tribal Housing Co-Operative Inc. (1998), 1998 CanLII 6408 (ON CA), 42 O.R. (3d) 46 (C.A.), at paras. 8, 10. As such, the doctrine of abuse of process is broader than res judicata and issue estoppel and applies to bar litigation that, if it proceeded, would “violate such principles as judicial economy, consistency, finality and the integrity of the administration of justice”: C.U.P.E., at para. 37.
 We agree with the motion judge that the whole evidentiary underpinning of this action is the same as that of the Royal Trust action and that it would be unfair and an abuse of process to allow the appellants to “in effect, re-litigate their case, with a new theory, to see if this one will succeed where previous theories have failed”. Moreover, the doctrine of abuse of process applies to prevent re-litigation of previously decided facts: Intact Insurance Company v. Federated Insurance Company of Canada, 2017 ONCA 73 (CanLII), 134 O.R. (3d) 241, at para. 28, leave to appeal refused,  S.C.C.A. No. 98; R. v. Mahalingan, 2008 SCC 63 (CanLII),  3 S.C.R. 316, at para. 46; C.U.P.E., at para 37. As the motion judge determined, the relief and issues put forward by the appellants in these proceedings “arise from the same relationships and subject matter that have already been dealt with by Perell J. and the Court of Appeal” in the Royal Trust action.