Fourth Amendment

Jacob Sullum | 2.4.2026 4:35 PM

In the 2013 case Florida v. Jardines, the Supreme Court held that police violated the Fourth Amendment when they deployed a drug-detecting dog on the front porch of a house without a warrant. But last year in United States v. Johnson, the U.S. Court of Appeals for the 4th Circuit said that was not true when police deployed a drug-detecting dog at the doorstep of an apartment.

The 4th Circuit was wrong, the Cato Institute argues in a brief urging the Supreme Court to review that decision. The appeals court's ruling "impermissibly curtails constitutional protections in the domestic setting where they matter most," say Cato lawyers Matthew Cavedon, Dan Greenberg, and Laura Bondank. "This Court has repeatedly explained the importance of Fourth Amendment protections for both the home and the area 'immediately surrounding and associated with' it."

The special status of that area, known as the "curtilage," was the justification for the Supreme Court's ruling in Jardines. Contrary to what the 4th Circuit held, Cavedon et al. argue, "the fact that other tenants have access to a common hallway—one steadfastly locked against outsiders who might seek to enter—does not remove the privacy afforded to the curtilage."

The case involves Eric Tyrell Johnson, a Maryland man who was convicted of federal drug and gun charges based on evidence discovered during a 2019 search of his apartment in Owings Mills. The warrant for that search, in turn, was based on a dog's "alert" after it sniffed the bottom of the door to Johnson's apartment. Johnson unsuccessfully sought to exclude the evidence from the search by arguing that the dog should not have been brought to his doorstep without a warrant.

That argument seems consistent with Jardines. "The officers were gathering information in an area belonging to [Joelis]........

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