Canada's new mandatory minimum sentences for drug offenders are based on "very bad criminal law policy" and constitute a threat to public health as well as the concept of judicial proportionality, former Supreme Court of Canada Justice Louise Arbour says. The law should, and almost certainly will, face a justifiable constitutional challenge, Arbour adds of the omnibus crime legislation, Bill C-10, which received royal assent in March (www.parl.gc.ca/HousePublications/Publication.aspx?DocidT65759&file=4). Forcing judges to impose minimum sentences for drug offences endangers the legal precept of proportionality, under which judges must tailor the level of punishment to the severity of the crime, adds the former United Nations high commissioner for human rights and former chief prosecutor of the International Criminal Tribunals for Rwanda and the former Yugoslavia. [continues 734 words]