In opinions on abortion and gay rights, U.S. Supreme Court Justice Antonin Scalia has taken an offensively narrow view of the Constitution’s guarantees of due process and equal protection.

But when it comes to the Fourth Amendment’s more specific protection against unreasonable searches, Scalia has been a strong voice for individual rights. That was the case again last week. Writing for a 5-4 majority, Scalia came down hard on police in Florida who, without having obtained a warrant, deployed a drug-sniffing dog at a homeowner’s front door.

Scalia said it was well-established Anglo-American law that the protection of the home against unreasonable searches extends to the area “immediately surrounding his house.” Nor did it matter that the law allows visitors to approach a front door.

Scalia wrote: “To find a visitor knocking on the door is routine (even if sometimes unwelcome); to spot that same visitor exploring the front path with a metal detector, or marching his bloodhound into the garden before saying hello and asking permission, would inspire most of us to — well, call the police.”