Ignorance of the law isn't an acceptable defense, even for police

It's already too easy for police to stop motorists they consider suspicious using the pretext of a minor violation of traffic laws. Law enforcement will enjoy even more leeway under Monday's misguided Supreme Court decision upholding the legality of stops based on an officer's misunderstanding of the law.

By a disappointingly lopsided 8-1 vote, the justices ruled that Nicholas Heien wasn't the victim of an "illegal seizure" when his car was stopped in 2009 by a member of the Surry County, N.C., sheriff's department. The routine stop turned into something more serious when Heien agreed to a search of the vehicle. The search turned up a sandwich bag containing cocaine.


Police may stop a car if they have reasonable suspicion that a crime has been committed. The officer told Heien and a friend who had been driving the car that it was stopped because the right brake light wasn't working. But it turned out that North Carolina law required only that a car be equipped with a singular "stop lamp on the rear of the vehicle." Heien's left light worked perfectly well.

The question for the court was whether the stop — which led to the search — was legal because the officer "reasonably" misunderstood what the law said. Writing for the court, Chief Justice John G. Roberts Jr. said yes, citing 19th century cases involving the seizures of ships or their cargo.

"To be reasonable is not to be perfect," Roberts wrote, "and so the 4th Amendment allows for some mistakes on the part of government officials, giving them fair leeway for enforcing the law in the community's protection." Yet there is a difference between providing some leeway for errors of fact — which are inevitable when police are making quick decisions in the field — and allowing police to act out of ignorance of a law they should know backward and forward.

In a concurring opinion, Justice Elena Kagan tried to minimize the importance of the ruling by suggesting that it would apply only when an officer was enforcing a "genuinely ambiguous" statute. Kagan noted that a separate section of North Carolina law refers to "rear lamps" in the plural.

That's small consolation for a decision that, as dissenting Justice Sonia Sotomayor put it, gives police additional authority to seize vehicles or individuals "so long as they can attach to their reasonable view of the facts some reasonable legal interpretation (or misinterpretation) that suggests a law has been violated." The result will be more fishing expeditions in the guise of enforcing minor traffic laws.

Ignorance of the law isn't an acceptable defense for ordinary citizens; neither should it be for the police.

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