The Supreme Court of Canada has made a forthright denunciation of the use of the death penalty in the US and more than 100 other countries.
In a landmark judgment, all nine judges said Canada should only agree to extradite people if they received assurances that the people would not face the death penalty in their subsequent trials.
The ruling said: "In the Canadian view of fundamental justice, capital punishment is unjust and should be stopped."
They said they were increasingly concerned about its use, given that wrongful convictions had recently been uncovered in Canada, Britain and the US. Canada stopped using the death penalty in 1976.
The ruling was made in the case of Mr Atif Rafay and Mr Sebastian Burns, who face charges of murdering Mr Rafay's parents and sister in the state of Washington in 1994. They fled across the border but were arrested in their home city, Vancouver, a year later.
Since then, their lawyers have been fighting to ensure the pair would not face the death penalty if they were found guilty.
The court also made it clear that it wanted the case to set a precedent, saying it would require exceptional circumstances in any future cases for alleged criminals to be extradited without such assurances being given. It is now up to the judiciary in Washington state to decide whether it will give the assurances that will now be necessary for the two men to be extradited.
Mr Vic Toews, justice spokesman for the opposition Canadian Alliance party, said he was concerned that the ruling could result in Canada becoming a haven for criminals.
But the federal justice minister, Ms Anne McLellan, denied this was a risk.
The court's ruling pointed out that the decision was unlikely to deter any country which wanted to prosecute someone for a serious crime just because it could not impose the ultimate sanction.
It also said there was evidence that a life in prison without release or parole was equally effective as a deterrent.
But with Canada and the US sharing the world's longest undefended border, government critics clearly feel the ruling could have made Canada a more desirable destination for fugitives.