The Supreme Court of Canada has ruled that police can deploy drug-detecting sniffer dogs for warrant-less searches against suspects, but only with "reasonable suspicion based on objective, ascertainable facts" of criminality.

The decisions mean that the Supreme Court agrees that the existing threshold should remain in place with regard to reasonable suspicion for police to conduct random public searches of people with drug-sniffing dogs.

The deployment of a dog trained to detect illegal drugs … may be carried out without prior judicial authorization where the police have a reasonable suspicion based on objective, ascertainable facts that evidence of an offence will be discovered. - Supreme Court of Canada decision, R. v. MacKenzie

Legal experts had been monitoring two decisions today regarding the use of drug-sniffing dogs, believing it would clarify what constitutes "reasonable suspicion" for when the animals can be called forth. The outcomes would decide whether police in both cases had breached the two men's charter rights to be free from unreasonable search and seizure.

In a ruling today for one of the men, Benjamin MacKenzie, the Supreme Court stated: "The deployment of a dog trained to detect illegal drugs using its sense of smell is a search that may be carried out without prior judicial authorization where the police have a reasonable suspicion based on objective, ascertainable facts that evidence of an offence will be discovered."

In 2006, MacKenzie, who is from Saskatchewan, was found with 14 kilograms of marijuana in his car trunk. But he was searched only after police pulled him over for driving just two kilometres an hour over the posted speed limit and deciding his eyes looked red. An initial police search came up with nothing before they brought in the sniffer dogs.

A year earlier, Nova Scotian Mandeep Chehil's cash purchase of a one-way ticket raised RCMP officers' eyebrows. Chehil was travelling alone when he landed in Halifax from Vancouver. In B.C., Mounties let their dogs search him and then found to have three kilograms of cocaine in his suitcase.

'Small victory'

Lower courts acquitted both men, reasoning that police did not have reasonable suspicion when the law enforcement officials set their dogs upon MacKenzie and Chehil for a sniff search. However, their acquittals were later overturned by appellate courts.

The Supreme Court decided today to dismiss both men's appeals.

CBC's Alison Crawford, reporting from Ottawa, said the rulings were not likely to please civil liberties groups.

"They had argued that this threshold allows police to catch up a lot of innocent people in those searches," she said.

"But they did have a small victory today at court because the Supreme Court of Canada rejected an application from the Attorney General of Ontario."

That application had argued that people should have no expectation of privacy in an airport setting. The Supreme Court of Canada begged to differ, saying there was "no compelling reason" as to why that should be so, saying the public should at least have a small expectation of privacy when flying.