The B.C. Supreme Court ruling involves the case of Donald Boutilier, who pleaded guilty in May 2012 to a number of offences including assault and robbery. The Crown asked that he be declared a dangerous offender, which carries the possibility of an indeterminate sentence.
His lawyer challenged the law, arguing changes put into place in 2008 under an omnibus crime bill violate Boutilier's charter rights because they removed the judges' discretion over declaring someone a dangerous offender.
Judge Peter Voith said the changes mean some offenders could be labelled dangerous regardless of whether they actually pose a risk to the public.
"A dangerous-offender designation, absent consideration of the treatment prospects for an offender, serves to permanently label an offender as dangerous when there may be 'clear evidence' that the offender, with treatment, does not pose a risk or poses a limited risk to the public," Voith said in a written decision.
A hearing is scheduled in the new year to determine what will happen to the law.
The 2008 law made several changes to how dangerous offenders are classified and how they are sentenced, generally making it easier to have a person with multiple convictions labelled dangerous.
Under the old regime, a dangerous-offender designation came with an automatic indeterminate sentence — a life sentence with no specified parole eligibility date — but it was up to a judge to determine whether such a designation was justified in the first place. Even repeat violent offenders could avoid the designation if there was evidence they could be treated or had already been rehabilitated and were no longer a danger.
The 2008 changes made a designation mandatory for anyone who is convicted of a "serious personal injury" crime and shows a pattern of dangerous behaviour. Three or more convictions are automatically considered to form such a pattern.
Indeterminate sentences are no longer mandatory and judges can instead resort to less-serious measures, such as a defined prison term or a long-term supervision order, if they believe the public would still be protected. However, the law sets a high burden before a judge can consider the lower punishment, and Voith's ruling concludes it is "inevitable" that a greater number of offenders will receive indefinite sentences.
Regardless of the sentence, the dangerous-offender designation is permanent.
Voith ruled the law violates the section of the Charter of Rights and Freedoms that deals with liberty and security of the person.
He will hear arguments in February about whether the violation means the law should be declared unconstitutional, or if it should be upheld as reasonable under the charter.
In the meantime, Crown spokesman Gordon Comer said it's too early to say how the court ruling could impact other dangerous offender hearings, which are not common.
He said no specific cases have been delayed in light of the recent judgment, though he said such decisions will be handled on a case-by-case basis
"It's just too early to know whether or not this is even going to affect other cases," he said.
The federal Justice Department did not return a request for comment.
Boutilier's defence lawyer, Gary Botting, said the law makes it extremely likely that offenders who don't pose any risk to the public will be locked up indefinitely.
"In the old regime, judges had lots of discretion, and that's why it seemed to be fair," said Botting.
"Prosecutors now have all the power to decide whether they're going to proceed with a dangerous-offender (application). Once they make a decision, there is nothing the judge can do to stop the train."
The case is the latest court challenge targeting the Conservative government's crime agenda.
In 2012, an Ontario judge struck down the new dangerous-offender provisions after concluding it requires defendants to prove they are not dangerous offenders. The defendant in that case, Roland Hill, died in prison soon after and the government decided not to pursue an appeal, as the lower-court decision was not binding.
Follow @ByJamesKeller on TwitterSuggest a correction