MLJ Volume 36-1.pdf - Robson Hall Faculty of Law

The Trial Judge's Four Discretions 189
general discretion that exists at common law which allows for the
exclusion of defence evidence where its prejudice substantially outweighs
its probative value; and fourthly, the “constitutionalized common law
discretion” arising out of the Charter and the Harrer decision which allows
for the exclusion of evidence to preserve a fair trial.
This article has shed new light on how each of these discretions
operates by analyzing each in relation to one another. It has been
determined that the exclusionary discretions differ quite markedly in their
scope. For example, the ambits of each of the discretions existing at
common law, from largest to smallest, may be listed in the following order:
i. The Seaboyer/Mohan discretion exercisable against Crown
evidence
ii. The Harrer discretion exercisable against Crown evidence
iii. The Seaboyer discretion exercisable against defence evidence
The Wray discretion is notably absent from the list. This is because, even
though it may still be good law in that it has not been specifically
discarded by the Supreme Court 213 it has fallen into disuse. To repeat, this
is because it has been subsumed by the Seaboyer discretion exercisable
against Crown evidence – the Seaboyer discretion captures all evidence that
would have been captured by the Wray discretion. Nonetheless, it is worth
underscoring where its ambit would lie with respect to the exclusionary
discretions identified in the above list since, as is evident in this article
itself, it is still the discretion commonly cited and used as a reference point
by the many judges and the small group of legal scholars attempting to
explain the scope and operation of particular exclusionary discretions
existing in law. Properly understood, the Wray discretion belongs at the
bottom of the list, since there is no question that its ambit is the most
restrictive.
Notwithstanding the findings of this article, it is readily apparent that
the exclusionary discretions discussed herein are not easily distinguishable,
nor easily comprehensible, and that there is probably overlap between
them. In fact, much about the nature of some of these discretions remains
a mystery. For example, is the balancing exercise that characterizes the
operation of the discretion to exclude Crown evidence at common law
213
Corbett, supra note 2 at para 739–740, per La Forest J (dissenting); Seaboyer, supra note
56 at paras 610–611. See also Sopinka et al, supra note 5 at para 2.57.