Out of Step: Why State High Courts Should Interpret State Constitutions to Provide Greater Protections Against Police Searches

Tom Burnett*

State high courts should not seek uniformity with federal law and other states concerning the rules for police searches. Instead, state courts should interpret their own constitutions and, when appropriate, find greater protections under their constitutional provisions than those afforded by the Fourth Amendment. By not lockstepping with the US Constitution, state high courts can independently protect individual rights, more accurately mirror societal expectations of privacy, and more efficiently address novel legal questions posed by police searches utilizing emerging technologies.

I. States ceding their authority to interpret their constitutions for a uniform approach weakens the protection of individual rights.

Two layers of constitutional protection are intended to enforce the right against unreasonable searches: the Fourth Amendment and analogous provisions in state constitutions. Under the Supremacy Clause,¹ the protections afforded by the Fourth Amendment against unreasonable searches create a baseline. Tethering the scope of similar state constitutional provisions to this federal baseline is known as lockstepping.² However, state high courts can also interpret their state constitutions as “font[s] of individual liberties, their protections . . . extending beyond those required by the Supreme Court’s interpretation of federal law.”³ By creating this dual constitutional system, the Framers ensured “a double security arises to the rights of the people.”⁴

No right is more fundamental than the security of one’s person and home. States should turn to their own constitutions when they find federal protections lacking. States’ ability to interpret their constitutions as granting greater rights than those found in the Fourth Amendment—even if the language is identical—is a structural safeguard against unreasonable searches. States’ abilities to both backstop and enhance the rights of their citizens are baked into a federalist system. In contrast, a uniform, lockstep approach would erase the “double security” envisioned by the Framers, absent states ratifying novel constitutional provisions.

Proponents of uniformity may argue lockstepping results in the predictable enforcement of police searches and that state lines should not dictate individual rights. However, Fourth Amendment protections already apply in every state—lockstepped or not. As such, there is minimal upside for states to pursue a uniform approach. Lockstepping only takes away from a state’s power to regulate policing within its borders. Lockstepping also runs the risk that federal precedent will be overturned, potentially casting doubt on whether state high court decisions remain good law.⁵ Independent interpretation avoids this pitfall by creating a body of state case law untethered from the whims of the federal judiciary.

II. State courts are better positioned to determine societal attitudes over reasonable expectations of privacy.

Justice Harlan’s concurrence in Katz v. United States came to establish the two-part test often used to evaluate police searches: (1) The defendant exhibited an actual expectation of privacy and (2) the expectation is “one that society is prepared to recognize as ‘reasonable.’”⁶ The first prong is subjective and can only be evaluated on a case-by-case basis. The second prong, however, attempts to define an objective societal expectation of privacy. The problem is that societal expectations of privacy vary by locale.

Katz and its kittens attempt to define society’s reasonable expectations of privacy on a national scale. However, the United States is composed of at least fifty-one societies—each with different traditions, attitudes, and expectations toward privacy and what constitutes appropriate policing. State courts are better situated to determine whether a search violates privacy expectations within their jurisdictions. For example, Oregon courts have expressed skepticism at even attempting to define a reasonable expectation of privacy, preferring to adjudicate police search cases through the lens of state constitutional rights.⁷ Such a decision is entirely Oregon’s prerogative, particularly if it mirrors the expectations of Oregonians.

Further evidence of localized attitudes toward privacy can be seen in the aftermath of California v. Greenwood. In Greenwood, the Supreme Court used the Katz framework to hold that American citizens have no reasonable expectation of privacy when placing garbage on the curb and that police can search this trash without a warrant.⁸ However, the Court noted: “Individual States may surely construe their own constitutions as imposing more stringent constraints on police conduct . . . .”⁹ Several states have done exactly that—rejecting Greenwood’s holding and finding their societies more-than-prepared to recognize a reasonable expectation their refuse will go unsearched.¹⁰

State courts declining to follow holdings like Greenwood are not outliers. Cases concerning search and seizure are where “state supreme courts have been most willing to break with U.S. Supreme Court precedent.”¹¹ At least thirty-three state high courts have found heightened search and seizure protections under their state constitutions.¹² In other words, the Fourth Amendment alone neither protects nor reflects the expectations of privacy recognized by Americans residing in a majority of states.

III. State courts and constitutions provide the speed and flexibility needed to address questions posed by police searches utilizing emerging technologies.

“In the precomputer age, the greatest protections of privacy were neither constitutional nor statutory, but practical.”¹³ Today, technological advances have changed the ways police conduct searches. What even constitutes a search is an evolving question. For example, in 2018, the Supreme Court held that the warrantless acquisition of cell-site location data did not fall within the third-party doctrine and constituted an illegal search under the Fourth Amendment.¹⁴ Courts are now being asked to determine the constitutionality of searches using technologies as diverse as drones,¹⁵ geofence warrants,¹⁶ and advanced DNA testing.¹⁷

In State v. Carbo, the Minnesota Supreme Court declined to rule on whether a single nucleotide polymorphism (SNP) profile created from items taken during a warrantless trash pull was an unconstitutional search.¹⁸ The defendant had voluntarily provided a DNA sample shortly after the SNP profile was made—which invoked the independent source doctrine and rendered the issue moot.¹⁹ In his concurrence, Justice Procaccini questioned the wisdom of continuing to treat modern DNA profiling as equivalent to collecting a fingerprint, noting:

SNP profiles contain several hundred thousand informationally rich segments of DNA, which can be decoded to predict distant genealogical relationships, disease carrier status, and aspects of physical appearance . . . . [T]he report delivered to law enforcement in this case used Carbo’s SNP profile to describe his physical traits (including skin, eye, and hair color), as well as to predict his family tree and ancestral origins dating to the late eighteenth century and stretching across continents. The report also contained a ‘‘phenotype prediction’’ that provided a digitally constructed portrait of Carbo’s appearance at age 25 [, Carbo’s age in 1986,] based on the genetic characteristics in his SNP profile.²⁰

Technological advances like SNP profiling and the constitutional questions they pose will require courts to reevaluate established doctrines. As in Carbo, state courts are likely to find themselves at the vanguard of these issues.

Although state courts may look to federal or other states’ laws for guidance, state courts are not bound by these decisions when interpreting their own constitutions. This flexibility allows for experimentation when regulating police use of emerging technologies, and “[i]f federal courts are hesitant to provide protection against police intrusion by newer technologies, state courts are increasingly well-positioned to extend these protections . . . .”²¹ The relative speed of state courts is also more likely to keep pace with technological innovation.

IV. Conclusion

State constitutions have protected citizens from unlawful searches since America’s founding. Prior to the incorporation of the Fourth Amendment in 1949, constitutional questions regarding local police searches were litigated under state constitutions.²² Even the very notion of the Fourth Amendment “was borrowed from the Massachusetts and Pennsylvania Constitutions.”²³ The computer age poses novel questions that may require novel interpretive solutions. State high courts should return to their constitutions, experiment in finding what works for their societies, and “continue to uphold . . . privacy rights as technology evolves.”²⁴

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* Tom Burnett, J.D. Candidate, University of St. Thomas School of Law Class of 2026 (Associate Editor).

1. U.S. Const. art. VI, cl. 2. ↩︎
2. See Earl M. Maltz, Lockstep Analysis and the Concept of Federalism, 496 Annals Am. Acad. 98, 99 (1988). ↩︎
3. William J. Brennan, Jr., State Constitutions and the Protection of Individual Rights, 90 Harv. L. Rev. 489, 491 (1977). ↩︎
4. The Federalist No. 51 (James Madison); see also Brennan, supra note 3, at 503 (“[O]ne of the strengths of our federal system is that it provides a double source of protection for the rights of our citizens.”). ↩︎
5. See Elizabeth Bentley, State Court Adherence to Decisions Incorporating Federal Constitutional Law, 110 Iowa L. Rev. (forthcoming 2025), for a more nuanced discussion of the precedential value of lockstepped state decisions. ↩︎
6. Katz v. United States, 389 U.S. 347, 361 (1967) (Harlan, J., concurring). ↩︎
7. State v. Goldberg, 483 P.3d 671, 675 (Or. 2021); State v. Campbell, 759 P.2d 1040, 1044 (Or. 1988). ↩︎
8. California v. Greenwood, 486 U.S. 35, 39–40 (1988). ↩︎
9. Id. at 43. ↩︎
10. See, e.g., State v. Wright, 961 N.W.2d 396, 420 (Iowa 2020); State v. Goss, 834 A.2d 316, 319 (N.H. 2003). ↩︎
11. Alicia Bannon, Fourth Amendment Lags Behind State Search and Seizure Provisions, State Ct. Rep. (May 31, 2024), https://statecourtreport.org/our-work/analysis-opinion/fourth-amendment-lags-behind-state-search-and-seizure-provisions [https://perma.cc/ZS6C-GPBA]. ↩︎
12. See generally Michael J. Gorman, Survey: State Search and Seizure Analogs, 77 Miss. L.J. 417, 418–64 (2007). ↩︎
13. United States v. Jones, 565 U.S. 400, 429 (2012) (Alito, J., concurring). ↩︎
14. Carpenter v. United States, 585 U.S. 296, 315 (2018). ↩︎
15. Long Lake Twp. v. Maxon, 15 N.W.3d 118, 129 (Mich. 2024) (holding the exclusionary rule did not preclude introduction of aerial photographs taken using a drone without a warrant). ↩︎
16. United States v. Smith, 110 F.4th 817, 838 (5th Cir. 2024) (“[G]eofence warrants are general warrants categorically prohibited by the Fourth Amendment.”). ↩︎
17. State v. Carbo, 6 N.W.3d 114, 122 (Minn. 2024). ↩︎
18. Id. ↩︎
19. Id. ↩︎
20. Id. at 128–29 (Procaccini, J., concurring). ↩︎
21. Matthew Radford, Note, Back to the Future: Revisiting State Constitutions to Protect Against New Technological Intrusions, 81 Wash. & Lee L. Rev. 1641, 1686 (2024). ↩︎
22. Wolf v. Colorado, 338 U.S. 25, 27–28 (1949) (incorporating the Fourth Amendment but not the exclusionary rule), overruled by Mapp v. Ohio, 367 U.S. 643, 655 (1961) (applying the exclusionary rule to the states). ↩︎
23. Radford, supra note 21, at 1654. ↩︎
24. Carbo, 6 N.W.3d at 127 (Procaccini, J., concurring). ↩︎