6 CARPENTER v. UNITED STATES Opinion of the Court analysis is informed by historical understandings “of what was deemed an unreasonable search and seizure when [the Fourth Amendment] was adopted.” Carroll v. United States, 267 U. S. 132, 149 (1925). On this score, our cases have recognized some basic guideposts. First, that the Amendment seeks to secure “the privacies of life” against “arbitrary power.” Boyd v. United States, 116 U. S. 616, 630 (1886). Second, and relatedly, that a central aim of the Framers was “to place obstacles in the way of a too permeating police surveillance.” United States v. Di Re, 332 U. S. 581, 595 (1948). We have kept this attention to Founding-era understandings in mind when applying the Fourth Amendment to innovations in surveillance tools. As technology has enhanced the Government’s capacity to encroach upon areas normally guarded from inquisitive eyes, this Court has sought to “assure[ ] preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted.” Kyllo v. United States, 533 U. S. 27, 34 (2001). For that reason, we rejected in Kyllo a “mechanical interpretation” of the Fourth Amendment and held that use of a thermal imager to detect heat radiating from the side of the defendant’s home was a search. Id., at 35. Because any other conclusion would leave homeowners “at the mercy of advancing technology,” we determined that the Government—absent a warrant—could not capitalize on such new sense-enhancing technology to explore —————— exclusively property-based approach. Post, at 1–2, 17–21 (THOMAS J., dissenting); post, at 6–9 (GORSUCH, J., dissenting). Katz of course “discredited” the “premise that property interests control,” 389 U. S., at 353, and we have repeatedly emphasized that privacy interests do not rise or fall with property rights, see, e.g., United States v. Jones, 565 U. S. 400, 411 (2012) (refusing to “make trespass the exclusive test”); Kyllo v. United States, 533 U. S. 27, 32 (2001) (“We have since decoupled violation of a person’s Fourth Amendment rights from trespassory violation of his property.”). Neither party has asked the Court to reconsider Katz in this case.