The Supreme Court of Canada has struck down some sections of the Criminal Code dealing with drinking and driving.
Three years ago, the government amended the law making it more difficult to fight driving-under-the-influence charges.
Under those new rules, anyone challenging a drunk-driving charge after testing over the legal limit on a roadside breathalyzer had to prove the machine malfunctioned or was misused, and that a high reading was the result.
Following that, the defendent had to prove further that they wouldn't have been drunk given the amount of alcohol they consumed — the so-called "Carter" defence.
Lawyers argued this reverse onus violates Canadians' Charter rights — and the principle of presumed innocence.
In a 5-2 decision, the Supreme Court partially agreed.
The court said Friday that once a defendant has proven a breathalyzer machine malfunctioned the rest doesn't matter.
But the court ruled that the onus of proof remains on the defendant to prove the breathalyzer or test was faulty.
The ruling stems from a case involving a Quebec woman who had argued the new law violated her constitutional rights by barring her from presenting a Carter defence. The trial judge agreed sections of the law were unconstitutional but still convicted her.
The woman paid her fine, but Quebec Crown prosecutors appealed on the basis that the application of the law needed clarifying.
The court ruled Friday that requiring a defendant to both prove that a breathalyzer had malfunctioned or been misused and establish a causal connection to a high reading "constitutes a serious infringement of the right to be presumed innocent," an infringement that "cannot be justified in a democratic society."
In a related case, R. v. Dineley, the court restored the acquittal of a man whose case was on adjournment when the law was changed to eliminate the Carter defence as an independent defence against a drunk-driving charge.
The court, in a split 4-3 ruling, decided the retroactive application of the legislation to his case substantially affected his rights.
The text of the cited decisions:
R. v. St‑Onge Lamoureux, 2012 SCC 57 http://scc.lexum.org.../12655/index.do
R. v. Dineley,2012 SCC 58 http://scc.lexum.org.../12656/index.do