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Officer’s mistake can’t be probable cause

ImageA police officer’s mistake of law cannot support probable cause to conduct a stop, the Seventh Circuit held on July 17.

In 2004, two Illinois police officers received an anonymous tip that a black male driving a maroon Buick possessed drugs and a handgun.

After seeing a vehicle matching the description, they followed the vehicle. When the driver, Demarco McDonald, came to a 90 degree curve in the road, he turned on his turn signal.

The officers then stopped him for “Improper use of turn signal.” As the officer approached the vehicle, he noticed a gun on the floor of the car.

McDonald was arrested and charged in federal court with felon in possession of a firearm.

What the court held

Case: U.S. v. McDonald, No. 05-3761.

Issue: If a police officer’s stop of a motorist is based on a mistake of law, is there probable cause, if the officer subjectively thought the motorist committed a traffic violation?

Holding: No. A police officer’s mistake of law cannot support probable cause to conduct a stop.

McDonald moved to suppress the gun. The district court denied the motion, concluding that, although the anonymous tip was not sufficient grounds for the stop, the stop was lawful because the officer reasonably believed that McDonald’s use of the turn signal was a violation of state law.

McDonald pleaded guilty, reserving his right to appeal the denial of his suppression motion. The Seventh Circuit reversed, in a decision by Judge Ann Claire Williams.

The court first concluded that a driver who continues to proceed on the same street after engaging his turn signal does not violate any Illinois traffic laws.

Having done so, the court turned to the issue of whether a mistake of law can justify a stop under the Fourth Amendment.

The court noted that the majority of circuits to address the issue have concluded that such a stop is unlawful, and concluded that those courts have correctly analyzed the issue.

Related Links

7th Circuit Court of Appeals

Related Article

Case Analysis

The court wrote, “An officer cannot have a reasonable belief that a violation of the law occurred when the acts to which an officer points as supporting probable cause are not prohibited by law.”

The court then declined to adopt a good-faith exception to the rule, concluding, “A stop based on a subjective belief that a law has been broken, when no violation actually occurred, is not objectively reasonable.”

Quoting the Ninth Circuit with approval, the court iterated, “To create an exception here would defeat the purpose of the exclusionary rule, for it would remove the incentive for police to make certain that they properly understand the law that they are entrusted to enforce and obey.” U.S. v. Lopez-Soto, 205 F.3d 1101, 1106 (9th Cir. 2000).

Finally, the court distinguished those cases in which an officer stopped a defendant based on a reasonable belief about a fact that later turned out to be wrong.

The court concluded “When an officer makes a stop based on a mistake of fact, we ask only whether the mistake was reasonable. In contrast to the circumstances in the ‘mistake of fact’ line of cases on which the government relies, even if McDonald acted exactly as Officer Pearce believed, his actions were not a violation of any Illinois state traffic law (emphasis in original).”

Accordingly, the court reversed.

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David Ziemer can be reached by email.

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