A Canadian perspective on constitutional proportionality review

Given the US Supreme Court's various struggles with proportionality review of sentences under the Eighth Amendment, I was intrigue to see this article recently posted on SSRN discussing how the Supreme Court of Canada has approached this same issue. The article authored by Lauren Witten is titled "Proportionality As a Moral Process: Reconceiving Judicial Discretion and Mandatory Minimum Penalties," and here is its abstract:

This article reconceives proportionality in sentencing as a constructive reasoning process rather than as an instrumental means of achieving a fair quantum of punishment.  It argues that the Supreme Court of Canada has wrongly adopted the latter view by determining the constitutionality of mandatory minimum sentences according to hypothetical outcomes. R v. Nur is a paradigmatic example of how this error presumes a false objectivity in proportionality assessments that leaves the Court vulnerable to critiques of judicial activism.

This paper claims that a process-based conception of proportionality offers a stronger defence of judicial discretion in sentencing than the current framework offers; it better respects institutional roles and provides a more principled basis for declaring the current structure of mandatory minimum penalties unconstitutional. The proportionality as a process theory contends that judges alone are capable of reconciling the values of three constituencies in sentencing — the offender, the judge, and the public — and that this tripartite justification is integral to moral punishment.  This paper shows how the process view of proportionality in sentencing is an implicit, but under-theorized, current in the law that should be explicitly developed as part of Canadian constitutional theory.