Toronto: Canada has lived up to its word in punishing a low-level ringleader of a genocide far from its borders, Désiré Munyaneza, who beat children to death who were tied in stacks, who raped dozens of people, and killed dozens, in Rwanda in 1994.

It is right to take aim at the culture of impunity, and to refuse to be a haven for the world's worst criminals. It is right not to allow a mass murderer to blithely enjoy the fruits of this country's good-natured, welcoming communities. Right, but not preferable.

Where possible, Canada should still strive to deport those alleged to have committed mass murder, assuming a fair justice system and the protection of witnesses. They should face justice in the jurisdiction where the crimes took place, because that is the best way to end the sense of impunity that helped begin the genocide.

Canada looked the other way for too long on Nazi war criminals, but in the late 1990s championed the International Criminal Court, and the related notion of universal jurisdiction, in which countries take up the right to punish war crimes and genocide committed outside their borders. But living up to its promises, in the Munyaneza case, meant going outside some Canadian norms of justice.

For instance, Mr. Justice André Denis of the Quebec Superior Court set out the facts of the case in a secret 350-page appendix to his verdict in May; the public is not allowed to see it. Several hearings were held abroad, mostly in secret. Witnesses had their anonymity protected: They testified behind screens, and were not named in court, or in the judgment. It may be that doing justice in Rwanda demands the utmost witness protection. One legal observer said the secrecy was "probably a necessary adjustment" for the reality of a war-crimes prosecution. But the "adjustments" should ultimately be given rigorous scrutiny by the Supreme Court of Canada.

There are also practical issues involved in prosecuting war crimes in Canada. Canada has a war-crimes budget of about $15-million, and this prosecution cost roughly $4-million. There may be hundreds of war criminals here. Unless a massive expansion of the war-crimes budget is planned, which is unlikely, the trials will serve largely as a token, or symbol, of the wish to do something about genocide. The sense of impunity will not end. Genocidal killers will continue to try to conceal themselves among the refugees and immigrants who come to Canada.

It is good that Canada has not fallen back on excuses for allowing vicious genocidal killers to live in freedom within its borders, and has instead chosen to make Mr. Munyaneza a guest of its prisons for at least the next 25 years.

But trying to stop war criminals from getting into Canada, and deporting them to face justice in the place where justice cries out to be done, remain the best ways to end the culture of impunity.