“Without minimizing the seriousness of the police officer’s conduct or in any way condoning it,” the Court of Appeal for Ontario ruled in Mr. Harrison’s case in February, “the exclusion of 77 pounds of cocaine, with a street value of several millions of dollars and the potential to cause serious grief and misery to many, would bring the administration of justice into greater disrepute than would its admission.” The case is now before the Canadian Supreme Court.

The United States is the only country to take the position that some police misconduct must automatically result in the suppression of physical evidence. The rule applies whether the misconduct is slight or serious, and without regard to the gravity of the crime or the power of the evidence.

“Foreign countries have flatly rejected our approach,” said Craig M. Bradley, an expert in comparative criminal law at Indiana University. “In every other country, it’s up to the trial judge to decide whether police misconduct has risen to the level of requiring the exclusion of evidence.”

But there are signs that some justices on the United States Supreme Court may be ready to reconsider the American version of the exclusionary rule. Writing for the majority two years ago, Justice Antonin Scalia said that at least some unconstitutional conduct ought not require “resort to the massive remedy of suppressing evidence of guilt.”

The court will soon have an opportunity to clarify matters. The justices will hear arguments on Oct. 7 about whether methamphetamines and a gun belonging to Bennie Dean Herring, of Brundidge, Ala., should be suppressed because the officers who conducted the search mistakenly believed he was subject to an outstanding arrest warrant as a result of careless record-keeping by another police department.