"[W]hen it comes to the Fourth Amendment, the home is first among equals." Florida v. Jardines, 569 U.S. 1, 6 (2013). As this Court has repeatedly stressed, "the sanctity of a person's living space" is entitled to "special protection." Lange v. California, 594 U.S. 295, 303 (2021). Given that "centuries-old principle," the right "to retreat into [one's] own home and there be free from unreasonable government intrusion" lies at the "very core" of the Fourth Amendment. Id.

Here, at 3 a.m. and without a warrant, law-enforcement officers brought a trained drug-detection canine to sniff the front door of Eric Tyrell Johnson's apartment home in the locked hallway of a multi-unit building. They sought to gather information about the interior of Mr. Johnson's home. The dog alerted to the presence of illegal substances inside—information officers could not have otherwise gathered without physically entering the home. In the Second and Seventh Circuits and in Illinois and Texas, the officers' conduct would have been a Fourth Amendment search requiring a warrant or an exception to the warrant requirement. But the Fourth Circuit below joined the Eighth Circuit and the high courts of Maryland, Minnesota, and North Dakota in holding that using a drug-detection canine at the door of an apartment home is not a Fourth Amendment search. In so doing, the court rejected Justice Kagan's concurrence in Jardines, 569 U.S. at 12-16, and deepened the split.

The question presented is whether police conduct a Fourth Amendment search when they use a drug-detection canine to sniff the door of an apartment home in a multi-unit building to determine whether there is contraband inside.

Whether police conduct a Fourth Amendment search when they use a drug detection canine to sniff the door of an apartment home in a multi-unit building to determine whether there is contraband inside