In Collins v. Virginia, the Supreme Court will decide what happens when two nearly categorical rules come into conflict: the ability of law enforcement to search your automobile based on probable cause alone, and the right to be free from searches of your home and its curtilage absent a warrant. The issue before the Court is whether the automobile exception to the warrant requirement applies to a vehicle that is parked on the curtilage of the home. Curtilage is the area “immediately surrounding a dwelling-house,” such as the front porch and driveway. For the purposes of the Fourth Amendment, the Court has described this area as “enjoy[ing] protection as part of the home itself.”

The “automobile exception” to the warrant requirement is an exception dating back to 1925. Under this exception, law enforcement may search your car, without a warrant, based on probable cause alone. In Carroll v. United States (1925), the Court justified this exception by pointing to the inherent mobility of automobiles. Because an automobile may be “quickly moved” by the time law enforcement retrieves a warrant, no warrant is necessary. In South Dakota v. Opperman (1976), the Court further justified this exception by describing the reduced expectation of privacy afforded to automobiles. The Court reasoned that because automobiles are subject to “pervasive and continuous regulation”—such as periodic inspection, licensing requirements, and police stops—people do not expect as much privacy in their automobiles.

While the Court has routinely upheld these justifications, applying the automobile exception to even motor homes, the protections afforded to the home and its curtilage have equally strong jurisprudential standing. To date, the Court has always required a warrant to search the home and its curtilage with only a “few specifically established and well-delineated exceptions.” These include pursuing a fleeing criminal, preventing destruction of evidence, and preventing imminent danger to others. The automobile exception does not fit neatly into any of these categories. Thus, two nearly categorical rules collide.

If the Court decides to apply the automobile exception to curtilage, it may signal an erosion of fundamental Fourth Amendment protection to the home in favor of effective law enforcement. Because the home and curtilage are interchangeable for Fourth Amendment purposes, law enforcement could theoretically search an automobile even inside the home itself. If the Court decides not to apply the exception, some may view it as an erroneous obstacle to effective policing. It might seem arbitrary that police can search a vehicle parked on the curb, but not one parked mere feet away on the driveway.

Whichever way the Court decides, Collins v. Virginia will have important implications for the Fourth Amendment balance between effective law enforcement and privacy.