Countless matters come before Canadian courts each year, resulting in thousands of published decisions that address a wide variety of legal issues. Each decision contributes to the increasingly vast body of case law that constitutes the common law. The proliferation of online databases has improved the accessibility of Canadian case law, resulting in innumerable decisions now being at the fingertips of litigants, lawyers, and the courts. Navigating the overwhelming body of case law requires careful attention to the circumstances in which a particular decision may or will be binding or persuasive if relied upon before another court.
Stare decisis
In Canada, "[c]ommon law courts are bound by authoritative precedent" (R v Comeau, 2018 SCC 15 at para 26, [2018] 1 SCR 342 [Comeau]). This fundamental principle, referred to as stare decisis, promotes predictability and consistency, and is critical "for guaranteeing certainty in the law" (Comeau at para 26). Stare decisis takes two forms: vertical stare decisis and horizontal stare decisis.
Vertical stare decisisVertical stare decisis dictates that, "[s]ubject to extraordinary exceptions, a lower court must apply the decisions of higher courts to the facts before it" (Comeau at para 26). This principle is of critical importance. Without it, "the law would be ever in flux — subject to shifting judicial whims or the introduction of new esoteric evidence by litigants dissatisfied by the status quo" (Comeau at para 26). In Saskatchewan, vertical stare decisis requires the Court of King's Bench to apply decisions of the Court of Appeal, and requires both the Court of King's Bench and the Court of Appeal to apply decisions of the Supreme Court of Canada.
Horizontal stare decisisHorizontal stare decisis, on the other hand, "applies to courts of coordinate jurisdiction within a province" (R v Sullivan, 2022 SCC 19 at para 65, 472 DLR (4th) 521 [Sullivan]). As the Court acknowledged in Sullivan at para 65, "[w]hile not strictly binding in the same way as vertical stare decisis, decisions of the same court should be followed as a matter of judicial comity, as well as for the reasons supporting stare decisis generally". Horizontal stare decisis is closely related to the principle of judicial comity, which requires "that judges treat fellow judges' decisions with courtesy and consideration" (Sullivan at para 75). Horizontal stare decisis seeks "to balance stability and predictability against correctness and the orderly...
