For Immediate Release: November 20, 2025

SCOTUS Fails to Keep a Tight Leash on Police K-9 Drug-Sniff Searches Into Vehicles, Raising Fourth Amendment Concerns

WASHINGTON, DC — In yet another ruling that contributes to the steady normalization of police overreach, the U.S. Supreme Court has refused to rein in police K-9 drug-sniff searches during traffic stops.

By declining to hear an appeal in Mumford v. Iowa, the Court let stand an Iowa Supreme Court ruling that allows police to rely on a drug dog’s intrusion into a car’s interior during a traffic stop—even when officers lack probable cause to believe the car contains contraband. In a 5-2 decision in Mumford v. Iowa, the Iowa Supreme Court upheld as constitutional a search in which a police K-9 placed its paws on a car door and inserted its snout through an open window before alerting to drugs.

The Rutherford Institute, joined by Restore the Fourth, had urged the U.S. Supreme Court to overturn the ruling, arguing that warrantless, nonconsensual intrusions into protected spaces violate the Fourth Amendment, which extends its protection to a person’s vehicle. The amicus brief further warned that allowing a police dog to breach the interior of a car provides no limiting principle: if a dog’s snout may trespass inside a vehicle without probable cause, then so might thermal-imaging devices, x-ray scanners, fiberscopes, or other police technologies.

“What this ruling makes clear is that no American is safe from government intrusion, not even during a routine traffic stop. This is how constitutional rights are lost—not in dramatic sweeps, but in small, incremental intrusions that courts refuse to check,” said constitutional attorney John W. Whitehead, president of The Rutherford Institute and author of Battlefield America: The War on the American People. “If a police dog’s snout can be used to justify a warrantless search of a car, then there is nothing to stop the government from using ever more intrusive technologies, surveillance tools, and police instrumentalities to invade our privacy with little to no judicial oversight.”

The case arose after an Iowa police officer initiated a traffic stop of Ashlee Mumford’s vehicle, claiming the last two numbers on her license plate were obscured by dirt and grime. The officer summoned a K-9 unit, and Mumford and her passenger were ordered out of the vehicle “for their own safety” while the handler walked the dog around the car to conduct a “free air sniff.” Because Mumford’s passenger had left his window open, the dog pushed its snout through the open window into the cabin before alerting to drugs. A subsequent search of the vehicle uncovered drugs in the glove compartment which apparently belonged to the passenger. Officers then searched Mumford’s purse—which she had taken with her upon exiting the vehicle—and found marijuana and a pipe.

Mumford moved to suppress all evidence found as a result of the K-9’s alert, but the Iowa Supreme Court ruled 5-2 that the dog’s intrusion through the open window of a legally stopped vehicle does not require the suppression of evidence under the Fourth Amendment. Two justices dissented, reasoning that if an officer cannot lawfully stick his head inside a car without probable cause, neither should a police dog—acting as an officer’s instrumentality—be permitted to do so. The dissent also questioned whether police could direct their drug dogs to climb entirely inside a vehicle’s passenger compartment. Pushing back against the Iowa Supreme Court’s characterization of the drug sniff intrusion as minimal, the amici warned that unconstitutional practices often gain a foothold through seemingly minor transgressions.

Anand Agneshwar, Anna K. Thompson, and Tamryn Holley of Arnold & Porter Kaye Scholer LLP advanced the arguments in the amicus brief.

The Rutherford Institute, a nonprofit civil liberties organization, defends individuals whose constitutional rights have been threatened or violated and educates the public on a wide spectrum of issues affecting their freedoms.

This press release is also available at www.rutherford.org.

Source: https://tinyurl.com/bdh4v37e

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