As-Applied Fourth Amendment Challenges to Lifetime GPS Monitoring Require Particularized Evidence of Unreasonableness

Introduction

In F.S. v. Missouri Department of Corrections, Division of Probation and Parole (Mo. banc Feb. 11, 2025), the Supreme Court of Missouri addressed whether Missouri’s statutory “lifetime supervision” regime—specifically mandatory GPS ankle monitoring under section 217.735.4—violates the Fourth Amendment as applied to a person who has completed prison and parole.

The appellant, F.S., was convicted by a jury in 2015 of statutory sodomy of an 11-year-old child (section 566.062), served a five-year sentence, and completed parole in 2020. Nonetheless, by statute, she remains subject to lifetime mandatory electronic monitoring that “identifies and records [her] location at all times.” The Department enforces this through an ankle bracelet collecting GPS data every minute, typically reviewed when the system generates an alert for entry into statutorily-driven “exclusion zones” (e.g., parks and schools).

F.S. brought a declaratory judgment action challenging section 217.735.4 under the Fourth and Fourteenth Amendments. At trial, she abandoned a facial challenge and pursued only an as-applied Fourth Amendment claim, contending that lifetime GPS monitoring is an unreasonable search in her circumstances—particularly given her post-release conduct and the asserted low recidivism risk for female sex offenders.

The key issue on appeal was not whether GPS monitoring constitutes a “search” in the abstract, but whether the statute’s application to F.S. was shown—on the record she made—to be unreasonable under the Fourth Amendment’s totality-of-the-circumstances balancing.

Summary of the Opinion

The Court affirmed the circuit court’s judgment for the Department. It held that F.S. failed to carry her burden on an as-applied constitutional challenge because she presented no particularized evidence demonstrating that lifetime GPS monitoring was unreasonable as applied to her. The Court emphasized that:

• Statutes are presumed constitutional and the challenger must show clear unconstitutionality.
• An as-applied challenge requires evidence about the challenger’s individual circumstances.
• F.S.’s reliance on the absence of reoffending/arrest since parole, and general testimony about female offender recidivism, did not establish her individual risk profile or unreasonableness.
• The circuit court made factual findings—supported by expert testimony—that GPS monitoring can deter recidivism and that child-victim sex offenders can reoffend over longer time horizons; F.S. did not challenge those findings, and appellate review defers to them.

The Court also declined to address broader arguments framed in terms of “other similarly affected individuals,” limiting its analysis to F.S.’s as-applied claim.

Analysis

Precedents Cited

Samson v. California, 547 U.S. 843 (2006)

Samson supplied the core Fourth Amendment framework used by the circuit court (and accepted by the Supreme Court as the governing standard): reasonableness depends on the “totality of the circumstances,” requiring courts to balance (1) the degree of intrusion on privacy against (2) the degree the search is needed to promote legitimate governmental interests.

In this case, the balancing was shaped by two trial-level determinations: (a) F.S.’s diminished privacy expectations due to her status as a convicted felon/sex offender and the extensive public sex-offender registration regime, and (b) the State’s strong interest in protecting children and preventing recidivism, with GPS monitoring found to be a deterrent tool. The Supreme Court did not reweigh the Samson balance on a new factual record; it held F.S. failed to introduce the individualized evidence needed to tip that balance in her favor.

Weinschenk v. State, 203 S.W.3d 201 (Mo. banc 2006)

Weinschenk anchored two appellate review principles critical to the outcome: (1) constitutional validity is reviewed de novo, but (2) statutes carry a presumption of constitutionality. The presumption matters most in an as-applied challenge where the challenger’s factual showing is thin: the Court will not “assume” unconstitutionality without evidence overcoming that presumption.

Black River Motel, LLC v. Patriots Bank, 669 S.W.3d 116 (Mo. banc 2023)

Black River Motel, LLC v. Patriots Bank provided the controlling articulation of the burden in an as-applied challenge: the challenger must show the statute was unconstitutional “as applied to their individual circumstances.” The Supreme Court treated this as the dispositive standard and repeatedly returned to F.S.’s failure to produce “particularized” evidence about her own risk and circumstances beyond generalities (gender-based recidivism averages; no known reoffending since parole).

White v. Dir. of Revenue, 321 S.W.3d 298 (Mo. banc 2010)

White v. Dir. of Revenue supported appellate deference to the trial court’s “view of the evidence” and refusal to “second guess” contested facts. This deference mattered because the circuit court made affirmative factual findings—e.g., that GPS monitoring can deter sexual reoffending and that child-victim offenders reoffend over longer periods—and F.S. did not successfully challenge those findings. The Supreme Court therefore treated those factual predicates as fixed when evaluating the as-applied constitutional claim.

State v. Strudwick, 864 S.E.2d 231 (N.C. 2021)

The circuit court cited State v. Strudwick for the proposition that a convicted felon’s (and particularly a sex offender’s) expectation of privacy is “duly diminished.” While not a Missouri case, it served as persuasive authority supporting the privacy side of the Samson balance—making it harder for F.S. to show that GPS monitoring, in her posture, crosses the Fourth Amendment’s reasonableness line.

Belleau v. Wall, 811 F.3d 929 (7th Cir. 2016)

The circuit court used Belleau v. Wall to focus the privacy inquiry on the “incremental” intrusion created by GPS monitoring beyond the privacy reductions already imposed by sex offender registration and public disclosure. Because Missouri law requires lifetime registration for certain offenders (the circuit court referenced section 589.400.4(3), RSMo Supp. 2018), the court viewed GPS monitoring as a comparatively “slight” additional intrusion—again supporting reasonableness under the Samson balancing framework.

Citizens United v. Fed. Election Comm'n, 558 U.S. 310 (2010)

The Supreme Court of Missouri invoked Citizens United v. Fed. Election Comm'n not for its First Amendment substance but for a procedural-as-applied principle: an as-applied challenge fails where there has been “no showing” that the asserted constitutional harm is imposed “in this case.” The citation reinforced the opinion’s central theme: F.S. did not build an evidentiary record demonstrating that GPS monitoring is unreasonable for her, as opposed to arguing from broad propositions.

Legal Reasoning

1. Framing the claim as strictly as-applied. F.S. abandoned her facial challenge and the Court limited its analysis accordingly. That choice elevated the importance of individualized proof: the question became whether section 217.735.4 was unreasonable for F.S., not whether it might be unreasonable in some hypothetical or in a broader class of cases.
2. Burden of proof and evidentiary posture controlled the outcome. The Court underscored that statutes are presumed constitutional and that the challenger bears the burden to show clear and undoubted unconstitutionality. In an as-applied posture, that burden is met (if at all) through evidence of the challenger’s “individual circumstances.” Here, F.S. effectively announced she would not present evidence beyond limited stipulated facts and legal argument. That strategic choice became fatal under Black River Motel, LLC v. Patriots Bank.
3. Non-reoffending since parole did not establish low future risk. The parties stipulated that, as of March 22, 2023, there were no violation reports and no known reoffending/arrest/prosecution since parole. The Court held this fact “does little” to prove low future risk, especially against the circuit court’s unchallenged findings that sex offenders generally pose recidivism risks and that child-victim offenders may reoffend over longer periods after release.
4. Generalized testimony about female sex offenders was not individualized proof about F.S. Although the Department’s expert acknowledged on cross-examination that female sex offenders have low recidivism risk generally, he did not offer an opinion on F.S.’s particular risk. The Court stressed that gender is only one factor in individualized risk assessment, and other features—like the involvement of a child victim—could weigh differently. Without individualized proof, the Court would not treat generalized demographic trends as sufficient to invalidate monitoring as applied to this offender.
5. Appellate deference to unchallenged factual findings stabilized the Samson balance. Under White v. Dir. of Revenue, the Supreme Court deferred to the circuit court’s factual findings, including that GPS monitoring can deter recidivism through exclusion zones and increased certainty/swiftness of consequences. Because those findings were not successfully attacked, the Court effectively treated the government-interest side of the balancing test as established on this record.
6. Related arguments (privacy severity; lack of review until age 65) failed for the same reason: no individualized record. The Court rejected F.S.’s assertion that the privacy intrusion was “profound” because she pointed to no evidence rendering the circuit court’s contrary finding clearly erroneous. Likewise, her argument that lifelong surveillance with no opportunity for review until age 65 is unreasonable failed because she again offered no evidence of how that feature operated unreasonably in her circumstances (even though section 217.735.5 provides discretionary termination authority in “appropriate cases” at age 65).

Impact

The decision’s practical importance lies less in announcing a new Fourth Amendment test (the opinion applies the familiar Samson balancing framework) and more in clarifying the litigation burden for challenging lifetime GPS monitoring in Missouri:

• As-applied challengers must build an individualized evidentiary record. Merely showing compliance, time since release, or citing general recidivism data will likely be insufficient without offender-specific proof (e.g., individualized risk assessment evidence, individualized facts showing the monitoring’s incremental intrusion, or facts showing lack of fit between monitoring and legitimate objectives in that particular case).
• Trial-level factual findings about deterrence and recidivism can be outcome-determinative on appeal. Because appellate courts defer to supported findings, challengers must actively contest adverse findings (through contrary expert testimony, cross-examination developed into a factual record, and proposed findings).
• The opinion implicitly encourages more developed “reasonableness” records. Future litigants may respond by introducing individualized clinical/risk evidence, evidence of specific burdens (employment effects, medical issues, daily-life restrictions), and evidence comparing less intrusive alternatives in light of the individual’s profile.
• The Court leaves broader constitutional questions open. Because the facial challenge was abandoned and the Court expressly limited the decision to F.S.’s circumstances, the statute’s application to different offenders (different crimes, tiers, time since offense, health conditions, etc.) remains open to future litigation on different records.

Complex Concepts Simplified

“As-applied” vs. “facial” challenge

A facial challenge argues a law is unconstitutional in all (or most) applications. An as-applied challenge argues the law may be valid generally but is unconstitutional when applied to the specific person in their specific circumstances. This case turned on the stricter proof demands of an as-applied claim.

Fourth Amendment “reasonableness” and the “totality of the circumstances”

Even if government action is a “search,” it is unconstitutional only if “unreasonable.” Courts weigh privacy intrusion against legitimate governmental needs. That balancing is fact-dependent and often determined by the record made at trial.

Diminished expectation of privacy

People with certain criminal justice statuses (e.g., probationers/parolees, and in some contexts convicted felons/registered sex offenders) may have reduced privacy expectations, which can make supervision-related searches more likely to be upheld as reasonable.

“Particularized evidence”

Evidence tied to the individual challenger—not just general statistics or general assertions. Here, the Court required proof about F.S.’s specific risk and circumstances, not only generalized claims about female offenders or a compliance history.

“Exclusion zones”

Geographic areas defined (here, automatically based on statutory restrictions) that trigger alerts if the monitored person enters them. The circuit court viewed exclusion zones as a deterrence mechanism by interrupting access to potential victim areas.

Conclusion

F.S. v. Missouri Department of Corrections, Division of Probation and Parole stands for a record-driven principle: an as-applied Fourth Amendment challenge to lifetime GPS monitoring under section 217.735.4 will fail absent particularized evidence showing unreasonableness in the challenger’s individual circumstances. By coupling the presumption of constitutionality with deference to unchallenged trial-court factfinding, the opinion signals that future challenges to lifetime monitoring in Missouri will be won or lost primarily on the depth and specificity of the evidentiary record—especially individualized risk evidence and concrete proof of incremental privacy intrusion.