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The author of this article, Timothy Sandefur, filed an amicus brief in support of the defendant on behalf of the Goldwater Institute. The Federalist Society takes no positions on particular legal and public policy matters. Any expressions of opinion are those of the authors. We do invite responses from our readers. To join the debate, please email us at firstname.lastname@example.org.
Arizona’s Constitution is virtually unique in its treatment of searches and seizures. Unlike its federal counterpart, which prohibits only “unreasonable” searches of “persons, houses, papers, and effects,” the Arizona Constitution promises that “[n]o person shall be disturbed in his private affairs, or his home invaded, without authority of law.” Only Washington State’s Constitution—from which this language was copied—contains the same language.
In State v. Mixton, the Arizona Supreme Court was asked to interpret this Clause in a way that would, in the words of Judge Jeffrey Sutton, “extend greater protections [for individual rights] than the Federal Constitution.” The court rejected this invitation and instead relied on what it called “the value in uniformity with federal law” to interpret the Clause as essentially identical with the Fourth Amendment.
Mixton was a child pornography case in which officers obtained information about the defendant’s physical location by delivering a subpoena to a software company which operates a messaging application that Mixton used to receive illegal images. Courts applying the Fourth Amendment have applied the so-called third party doctrine to hold that officers need not obtain a warrant before seeking evidence from someone to whom the suspect has voluntarily given the information. Accordingly, the Arizona Supreme Court held that officers had not violated Mixton’s Fourth Amendment rights. But Mixton also argued that the state’s Private Affairs Clause nevertheless required officers to obtain a warrant, citing Washington court decisions that have refused to adopt the third party doctrine under that state’s Private Affairs Clause.
This argument confronted an anomaly, however: despite the fact that the two states’ Private Affairs Clauses are identical, Arizona courts have almost entirely ignored Washington Private Affairs precedent. Indeed, while the Evergreen State’s courts have developed a robust state-based jurisprudence interpreting that state’s clause, Arizona courts have done the opposite. In its first Private Affairs case—Malmin v. State in 1926—the Arizona Supreme Court declared that “although different in its language” from the federal Constitution, the clause “is of the same general effect and purpose as the Fourth Amendment, and for that reason, decisions on the right of search under the latter are well in point.” Since then, with only a few relatively insignificant exceptions, Arizona courts have interpreted the clause as if it were identical to the Fourth Amendment. This is incongruous, given that Arizona courts have followed Washington precedent when interpreting other provisions of its constitution that were copied from Washington’s. Some have argued that it contravenes the Arizona’s founders’ intentions; they expressly rejected the proposal to copy the Fourth Amendment’s language because they hoped to provide Arizonans with greater protections than those available under the federal Constitution.
Perhaps the most significant difference between the federal and state constitutions is that the Private Affairs Clause contains no reference to reasonableness; unlike the Fourth Amendment, the clause requires “lawful authority” for all searches, whether reasonable or not. This absence of a “reasonableness” element has led Washington courts to reject many of the exceptions to the warrant requirement fashioned by federal courts, because those exceptions have arisen from interpretations of “reasonableness.” For example, the Fourth Amendment does not require warrants for mandatory traffic checkpoints or inventory searches, because these are not “unreasonable.” But Washington courts have refused to adopt these exceptions under the Private Affairs Clause, because the clause bars even reasonable searches absent lawful authority. Arizona courts, however, have done the reverse. Since Malmin, they have interpreted the clause as essentially identical to the Fourth Amendment. Until Mixton, however, it never explained why.
In its 4-3 decision, the court ruled that officers did not violate Mixton’s rights under the clause and offered five reasons why it followed federal Fourth Amendment precedent instead of Washington Private Affairs Clause precedent. First, pointing to Malmin, it observed that “since statehood,” Arizona courts have viewed the clause as effectively redundant of the Fourth Amendment. Second, it claimed there was no “affirmative evidence” that the clause’s authors specifically intended to bar “use of a subpoena to obtain a business record to facilitate a legitimate criminal investigation.” Third, officers had not read the “contents of [Mixton’s] communication[s],” but only acquired location information. Fourth, there is “utility” in having “uniform state and federal criminal rules,” and state courts have reached a “consensus” that such location information is not constitutionally protected. Finally, although the clause does not expressly refer to reasonableness, determining whether something is a private affair “necessarily include[s] an assessment of the reasonableness” of that claim.
The three dissenters called this reasoning “curious and perplexing.” First, the dissenters argued that although it is true that, since Malmin, Arizona courts have viewed the clause as effectively redundant of the Fourth Amendment, that does not mean that Malmin was right. Second, the Arizona constitutional convention’s records are notoriously spotty, but Arizona courts have nevertheless followed Washington precedent relating to other clauses borrowed from that state’s constitution, and the records of debates over the Private Affairs Clause are sufficient to show that the clause’s wording “was deliberately chosen as an alternative” to the Fourth Amendment, in order to provide stronger protections for personal information. Third, while Mixton did not involve the contents of communications, information about “which websites a person has visited” is nevertheless personally revealing. As for the value of “uniformity with federal law,” or a consensus among the states, the framers and adopters of Arizona’s Constitution rejected uniformity by choosing not to copy the Fourth Amendment, and the “consensus” of other states is irrelevant, since their constitutions contain no Private Affairs Clauses.
The dissenters argued that the majority’s final reason—that reasonableness is inherent in the privacy determination—was more plausible, but they preferred a more objective approach: “we would ask (1) whether the search encompasses intimate details of a person’s life, and (2) whether the disclosure of information was made for a limited purpose and not for release to other persons for other reasons.” This, they argued, would avoid the “inherent subjectivity” of that plagues Fourth Amendment reasonableness inquiries.
The Mixton decision has significance far beyond the question of searches and seizures, however. As the dissenters asked, “if the framers wanted to craft language that would be enforced on its own terms, how could they have better done so than to reject one set of words and deliberately adopt another?” If the fact that the state constitution’s language differs entirely from that of the federal Constitution—because its framers wanted the two documents to mean different things—can be overlooked in service of a policy of uniformity, then “by what standard we will determine when to give independent meaning to our state constitutional language in other contexts[?]” Whether the majority’s desire to harmonize state and federal law will also affect other state constitutional provisions must await further decisions.
 Ariz. Const. art. II § 8.
 Wash. Const. art. I § 7. Washington’s Constitution was written in 1889; Arizona’s in 1910. In the later twentieth century, other states began adding express protections for “privacy” to their state constitutions, but these provisions were focused primarily on rights of personal intimacy, whereas the Washington and Arizona constitutions’ reference to “private affairs” had a broader sweep. See Timothy Sandefur, The Arizona “Private Affairs” Clause, 51 Ariz. St. L.J. 723, 726–40 (2019).
 No. CR-19-0276-PR, 2021 WL 79751 (Ariz. Jan. 11, 2021).
 Jeffrey S. Sutton, 51 Imperfect Solutions 66 (2018).
 Mixton, 2021 WL 79751 at *7.
 United States v. Miller, 425 U.S. 435 (1976); Smith v. Maryland, 442 U.S. 735 (1979).
 Mixton, 2021 WL 79751 at **2–6.
 State v. Gunwall, 106 Wash. 2d 54 (1986); State v. Miles, 160 Wash. 2d 236 (2007).
 See Sandefur, supra note 2 at 757–61.
 30 Ariz. 258 (1926).
 Id. at 261.
 Those exceptions only began in the 1980s, when the Arizona Supreme Court for the first time asserted that the clause provides stronger protections for individual rights than the federal Constitution. In State v. Bolt, 142 Ariz. 260 (1984), and State v. Ault, 154 Ariz. 207 (1987), it held that the clause provides stronger protections for searches of the home. In Rasmussen v. Fleming, 154 Ariz. 207 (1987), it declared that the right to refuse medical treatment was a private affair protected by the clause. These exceptions to Malmin, however, are relatively insignificant given that subsequent federal decisions held that the federal Constitution protects these rights as well—and that the Fourth Amendment is already at its strongest in cases involving homes. See Sandefur, supra note 2 at 763-65.
 See, e.g., Bailey v. Myers, 206 Ariz. 224, 230 (Ct. App. 2003); Mountain States Tel. & Tel. Co. v. Arizona Corp. Comm’n, 160 Ariz. 350, 355 (1989).
 See Sandefur, supra note 2 at 726; Charles W. Johnson & Scott P. Beetham, The Origin of Article I, Section 7 of the Washington State Constitution, 31 Seattle U. L. Rev. 431, 435–36 (2008).
 See, e.g., Michigan Dep’t of State Police v. Sitz, 496 U.S. 444, 451–55 (1990).
 See, e.g., S. Dakota v. Opperman, 428 U.S. 364, 368–71 (1976).
 See State v. Stroud, 720 P.2d 436, 441 (Wash. 1986) (inventory searches); City of Seattle v. Mesiani, 755 P.2d 775, 777 (Wash. 1988) (checkpoints).
 Mixton, 2021 WL 79751 at *6.
 Id. at *8.
 Id. at *3.
 Id. at *13.
 Id. at *9.
 Id. at *20 (Bolick, J., dissenting).
 Id. at *19–20 (Bolick, J., dissenting).
 Id. at **18, 23 n.3 (Bolick, J., dissenting); see also Sandefur, supra note 2 at 735–36; Johnson & Beetham, supra note 14 at 444–47, 454–56.
 Mixton, 2021 WL 79751 at *26 (Bolick, J., dissenting) (citation omitted).
 Id. at *7.
 Id. at *18 (Bolick, J., dissenting).
 Id. at *24 (Bolick, J., dissenting).
 Id. at *26 (Bolick, J., dissenting).
 Id. at **22 n.2, 25 (Bolick, J., dissenting).
 Id. at *18 (Bolick, J., dissenting).
 Id. at *20 (Bolick, J., dissenting).