Canada set an important example of decency when it offered a formal apology and compensation worth millions of dollars to a Syrian-born Canadian citizen who was a victim of President Bush’s use of open-ended detention, summary deportation and even torture in the name of fighting terrorism.

Last week’s announcement by Prime Minister Stephen Harper came more than four years after the nightmare began for the Canadian, Maher Arar, a 36-year-old software engineer. On his way back from a family vacation, he was detained by U.S. officials at Kennedy Airport on the basis of unsubstantiated information from the Canadian police. After being held in solitary confinement in a Brooklyn detention center and interrogated without proper access to legal counsel, he was sent to Syria, where he was imprisoned for nearly a year and tortured.

It was all part of a legally and morally unsupportable practice known as extraordinary rendition, the deportation of terrorism suspects to countries where the regimes are known to use torture and to disdain basic human rights protections.

Four months ago, a Canadian government panel concluded that Mr. Arar had never had a terrorism connection, and that Americans had misled Canada about their plans for him. The Bush administration stonewalled the inquiry. It has responded to a new Canadian request to remove Mr. Arar from a United States security watch list by rudely telling Canada, its democratic northern neighbor and strategic ally, to mind its own business.