The U.S. Supreme Court has held that a suspicionless ''dog sniff'' at a routine traffic stop is not a violation of the Fourth Amendment; therefore, appeals court erroneously reversed trial court's denial of defendant's motion to suppress marijuana detected by a police canine unit after a traffic stop.

Two Joliet police officers stopped defendant Jamyra Bew's car in the early morning hours of Feb. 21, 2002, after seeing the car stop at an intersection with its front tires in the crosswalk. The defendant was unable to produce either a driver's license or proof of insurance.

When the officers checked on the defendant's license they discovered it had been suspended. The officers then placed the defendant and her passengers in the backseat of their squad car because the car was being impounded pursuant to city policy. Although the officers lacked an articulable suspicion of the presence of marijuana or any other illegal drugs, they asked for a canine unit. When the canine unit arrived, one of the dogs ''alerted'' on the trunk.

The officers opened the trunk and discovered a large brick of cannabis weighing more than 37 pounds. The defendant was charged with unlawful possession of cannabis with intent to deliver. The defendant filed a motion to suppress the defendant's statements but did not move to suppress the evidence of the cannabis. The trial court denied the motion and she was found guilty.

On appeal, the defendant argued that she had been denied the effective assistance of counsel because of counsel's failure to file a motion to suppress. The defendant argued that she was prejudiced because the evidence should have been suppressed and the state could not have prosecuted her without it.

The appeals court reversed the defendant's conviction, finding that under People v. Cox, 202 Ill.2d 462 (2002), a motion to suppress enjoyed a reason able probability of success at trial because the officers had no suspicion of contraband in the vehicle when they requested the canine unit.

The state sought leave to appeal to the Supreme Court, which entered a supervisory order directing the appeals court to vacate its decision and reconsider in light of People v. Caballes, 221 Ill.2d 282 (2006) and Illinois v. Caballes, 543 U.S. 405 (2006). On remand, the appeals court continued to rely on Cox and didn't provide an adequate analysis of the Caballes decision. The state again sought leave to appeal. The Supreme Court granted its petition and reversed the appeals court.

The Supreme Court said that at the time of the defendant's trial, Cox was controlling law. Cox held that police officers violate the Fourth Amendment if they do not have ''specific and articulable facts'' to justify the use of a canine unit during a routine traffic stop.

In this case, the police officers testified that they had no suspicion of contraband when they called for a canine unit. Therefore, Cox would have mandated the exclusion of the marijuana absent the state's proving an exception to the Fourth Amendment's probable cause and warrant requirements.

In Caballes, however, the U.S. Supreme Court rejected a Fourth Amendment analysis. The court held that ''the use of a well-trained narcotics-detection dog … during a lawful traffic stop generally does not implicate legitimate privacy interests.… Any intrusion on respondent's privacy expectations does not rise to the level of a constitutionally cognizable infringement.''

''After the Caballes decisions, it is clear that a suspicionless dog sniff at a routine traffic stop is not a violation of the Fourth Amendment. Therefore, there is no basis to claim that a dog sniff is illegal merely because the officers lacked 'specific and articulable' facts before calling a canine unit. To the extent that Cox held otherwise, Cox is not expressly overruled,'' the Illinois Supreme Court said.

After Cox, there are still grounds available to challenge the admissibility of evidence found after a dog sniff of a car during a routine traffic stop, the state Supreme Court said. These include the duration of the stop, the initial lawfulness of the detention and the training and reliability of the canine and its handler.

People v. Jamyra E. Bew, No. 104084. Justice Rita B. Garman wrote the court's opinion with Chief Justice Robert R. Thomas and Justices Charles E. Freeman, Thomas R. Fitzgerald, Thomas L. Kilbride, Lloyd A. Karmeier and Anne M. Burke concurring. Released March 20.