The officer’s entering through an open door didn’t require knock-and-announce at common law. United States v. Sherrod, 2020 U.S. App. LEXIS 22296 (8th Cir. July 17, 2020):
In evaluating the Fourth Amendment’s protection against unreasonable searches and seizures, the Supreme Court has “looked to the traditional protections against unreasonable searches and seizures afforded by the common law at the time of the framing.” Wilson v. Arkansas, 514 U.S. 927, 931 (1995). The Court observed that even though the common law “protected a man’s house as ‘his castle of defense and asylum,'” id. (quoting 3 W. Blackstone, Commentaries * 288), it has been long recognized that “‘when the King is party, the sheriff (if the doors be not open) may break the party’s house, either to arrest him, or to do the execution of the King’s process, if otherwise he cannot enter,'” id. (quoting Semayne’s Case, 77 Eng. Rep. 194, 195 (K.B. 1603)). But the ability to break open a door is limited by “an important qualification” namely that “‘before he breaks it, he ought to signify the cause of his coming, and to make request to open doors.'” Wilson, 514 U.S. at 931 (quoting Semayne’s Case, 77 Eng. Rep. at 195-96). Thus, the Court had “no doubt that the reasonableness of a search of a dwelling may depend in part on whether law enforcement officers announced their presence and authority prior to entering.” Id.
Semayne’s Case also says that “[i]n all cases when the door is open the sheriff may enter the house, and do execut[e] at the suit of any subject, either of the body, or of the goods.” 77 Eng. Rep. at 197 (emphasis added). So, at common law the knock-and-announce rule hinged on whether the sheriff or bailiff confronted an open or closed door. See id.; Hodges v. Marks, 79 Eng. Rep. 414, 415 (K.B. 1615) (upholding an arrest after a bailiff entered a home through an open door and seized the arrestee); see also Steagald v. United States, 451 U.S. 204, 217 n.11 (1981) (observing at the common law “an open outer door was apparently regarded as the equivalent of a consent of the occupant for the constable to enter the home and conduct a search.”). The Fourth Amendment does not require officers to knock and announce their presence before entering an open door.
The knock-and-announce rule’s limited application to closed but not open doors makes sense in light of the rule’s underlying purposes. The rule protects individuals from harm that may flow from an unannounced forced entry, protects property by allowing individuals to comply with commands, and also protects “those elements of privacy and dignity that can be destroyed by a sudden entrance.” Hudson v. Michigan, 547 U.S. 586, 594 (2006); see also Mendoza, 281 F.3d at 717 (same). A closed door stands between officers and a home’s occupants in a way that an open door obviously does not. Where a door is open officer and occupant each have increased visibility into and out of a home. This increased visibility not only eliminates a potential forced entry, it may also provide notice of an impending interaction—especially if officers are in uniform. And when a door is open this “especially private sphere” is exposed to any passerby. See Florida v. Jardines, 569 U.S. 1, 14 (2013) (Kagan, J., concurring). Requiring officers to adhere to the knock-and-announce rule when facing an open door would “force [officers] to comply with formalistic rules when the circumstances direct otherwise.” Mendoza, 281 F.3d at 717.
Even though the knock-and-announce rule does not apply here, Officer Trost’s conduct does not escape Fourth Amendment scrutiny. “The Fourth Amendment says nothing specific about formalities in exercising a warrant’s authorization.” United States v. Banks, 540 U.S. 31 (2003). Instead its “touchstone is reasonableness … measured in objective terms by examining the totality of the circumstances.” Ohio v. Robinette, 519 U.S. 33, 34 (1996) (citation omitted). Our job is to assess reasonableness case by case. Banks, 540 U.S. at 35-36.