Court Puts a Leash on Dog Sniffs

Steven D. Schwinn, John Marshall Law School

The Supreme Court ruled today in Rodriguez v. United States that the Fourth Amendment prohibits a dog sniff that extends the duration of an otherwise lawful traffic stop, as measured by the time it reasonably takes an officer to complete the mission of the stop. But the ruling doesn't end the case: The Court sent the case back to the lower court for determination of whether the dog sniff was nevertheless independently justified under the Fourth Amendment.

We reviewed the oral arguments in the case here.

The case arose when an officer pulled Rodriguez over for a traffic violation, issued a warning, then engaged in a dog sniff (which revealed drugs, which led to Rodriguez's prosecution). In other words, the dog sniff came after the purpose, or mission, of the traffic stop expired and thus extended the stop beyond the period reasonably required to complete the mission. The Court previously ruled in Illinois v. Caballes that the Fourth Amendment tolerates a dog sniff in the course of an otherwise lawful traffic stop. But this case asked whether the Fourth Amendment also allowed that sniff when it extended the length of the stop.

The Court said no. Justice Ginsburg wrote for the Court, including Chief Justice Roberts and Justices Scalia, Breyer, Sotomayor, and Kagan. She wrote that a dog sniff that extends the length of the stop violates the Fourth Amendment, without some independent justification for it.

So: How to know if a dog sniff extends the length of the stop? Look to the officer's mission in making the stop in the first place: the "time reasonably required to complete [the stop's] mission."

Because the Court refused to draw a bright line at the point when an officer issues a ticket (and instead looked to the total time of the stop, whenever the mission is complete), the rule could mean that some dog sniffs in the course of a traffic stop (upheld under Caballes) would now violate the Fourth Amendment. Again, the touchstone is whether the sniff extends the "time reasonably required to complete [the stop's] mission."

The Court rejected the Eighth Circuit's holding that the sniff was reasonable because it only extended the time of the stop a little bit.

Justice Thomas wrote the principal dissent, joined by Justices Kennedy and Alito. Justice Thomas argued that because the stop was reasonably executed the sniff was OK.

He also argued that there was independent justification for the dog sniff--a point that Justice Alito also made in a separate dissent, but a point that Justice Kennedy did not join. The district court found that there was no independent justification for the sniff, but the Eighth Circuit did not rule on the question.

The case now goes back to the Eighth Circuit for a ruling on this issue. If the lower court finds an independent justification for the sniff (for reasons described by Justices Thomas and Alito, for example), then the evidence (drugs) can come in, and Rodriguez could still be convicted.