The Howell Rule: Qualified Immunity Shields Warrantless Entry When Officers Smell Marijuana After Announcing Their Presence

Introduction

In Matthew Howell v. Justin McCormick, No. 24-5570 (6th Cir. Aug. 25, 2025), the United States Court of Appeals for the Sixth Circuit confronted a tangle of Fourth Amendment questions arising from a late-night house-mate dispute in Nashville, Tennessee. Matthew Howell and his girlfriend, Alisha Brown, sued six Metro Nashville police officers and their municipal employer under 42 U.S.C. § 1983, alleging unconstitutional warrantless entry, false arrest, seizure of property, and malicious prosecution. The appellate court affirmed summary judgment for all defendants, clarifying several unsettled points of federal constitutional and municipal liability law. Chief among them is a new, highly practical precedent—dubbed here “the Howell Rule”—holding that:

When officers approach a residence, reveal their presence, and immediately detect the odor of marijuana, existing circuit and out-of-circuit case law is too divided to “clearly establish” that a warrantless entry violates the Fourth Amendment; qualified immunity therefore applies, even if a jury might ultimately find no exigent circumstances.

Beyond the exigent-circumstances discussion, the decision revisits probable-cause requirements for arrest and prosecution, the retroactivity of Chiaverini, the limits of municipal liability under Monell, and permissible temporary detention techniques under Terry. This commentary maps the opinion’s logic, contextualises the authorities cited, and assesses its future impact.

Summary of the Judgment

Warrantless Entry: The court refused to decide whether exigent circumstances actually existed, but held that no “clearly established” precedent prohibited the officers’ entry once they smelled marijuana after knocking. Qualified immunity therefore barred liability.
Arrest of Howell: Eyewitness statements from the complaining house-mate supplied probable cause for aggravated assault; the arrest was constitutional.
Detention of Brown: Brown’s 30–45-minute handcuffing was at most a Terry detention. No case clearly established that such a brief restraint, in a house containing firearms and the odor of marijuana, was unconstitutional.
Alleged Car “Seizure”: Even assuming officers helped move Howell’s vehicle, no governing authority put them on notice that this assistance amounted to an unreasonable seizure.
Malicious Prosecution: Probable cause for at least one indicted charge (aggravated assault) doomed Howell’s claim, and the later Supreme Court decision in Chiaverini could not retroactively defeat qualified immunity.
Municipal Liability: Plaintiffs failed to prove any unconstitutional Metro Nashville policy or longstanding custom; summary judgment for the municipality was affirmed.

Analysis

1. Precedents Cited and Their Influence

a. Warrantless Entry / Exigent Circumstances

Florida v. Jardines, Brigham City v. Stuart, Payton v. New York – re-stated the presumption against home entry without a warrant.
Kentucky v. King (2011) – abolished bright-line “police-created exigency” doctrine; the Sixth Circuit used King to justify applying a flexible, fact-specific approach that looks only to objective circumstances.
Johnson v. United States (1948) – distinguished because officers there smelled narcotics before revealing their presence; in Howell the smell occurred after disclosure, creating risk of destruction.
Out-of-Circuit Exigent-Smell Cases – e.g., United States v. Grissett (4th Cir. 1991), United States v. McMillion (3d Cir. 2012). The court relied on this “fractured” body of persuasive authority to conclude the law was unsettled, fortifying qualified immunity.

b. Arrest & Probable Cause

District of Columbia v. Wesby (2018) – emphasised low threshold for probable cause and the “demanding” standard for overcoming qualified immunity.
Ahlers v. Schebil, Farris v. Oakland County – Sixth Circuit precedents holding eyewitness allegations alone generally suffice for probable cause unless officers have reason to doubt credibility.

c. Malicious Prosecution

Thompson v. Clark (2022) – confirmed existence of a Fourth Amendment malicious-prosecution claim.
Chiaverini v. City of Napoleon (2024) – introduced charge-by-charge analysis, but the court treated it as new law, not clearly established at the time of Howell’s prosecution.

d. Municipal Liability

Monell v. Department of Social Services – liability attaches only to official policy or custom.
Pineda v. Hamilton County, Thomas v. City of Chattanooga – reiterated requirement of a “clear and persistent pattern” of similar violations.

2. Court’s Legal Reasoning

Step-wise Qualified Immunity Framework
The panel adhered to the two-step inquiry: (1) Was there a constitutional violation? (2) Was the right clearly established? Where the answer to the second question was plainly “no,” it skipped an in-depth ruling on the first, exemplifying judicial economy.
Specificity Requirement Heightened for Exigent-Circumstance Entries
Echoing Wesby and Rivas-Villegas, the court demanded plaintiff-side precedent “with a high degree of specificity,” particularly because exigent-circumstance analysis is highly fact-bound. General statements (e.g., “home entry without a warrant is presumptively unconstitutional”) were deemed inadequate.
Use of Out-of-Circuit Case Law to Gauge Clarity of the Law
The panel stressed that where several circuits bless similar conduct, a Sixth Circuit officer cannot be “plainly incompetent.” This placement of inter-circuit consensus (or discord) inside the clearly-established inquiry is a significant doctrinal development.
Retroactivity and Qualified Immunity
The panel refused to apply Chiaverini retroactively, holding that officers are judged by the law as it existed when they acted. This locks in protective qualified immunity even when Supreme Court doctrine changes later.

3. Likely Impact of the Decision

Exigent-Circumstance Litigation: Plaintiffs challenging warrantless entries based on “odor plus awareness” now face an additional hurdle. Unless and until the Sixth Circuit (or Supreme Court) squarely rules that such facts are not exigent, officers will continue to enjoy qualified immunity.
Municipal-Policy Drafting: The court’s rejection of challenges to Nashville’s domestic-abuse and warrantless-search directives encourages municipalities to keep policies broadly worded—so long as they reference constitutional constraints.
Chiaverini Retroactivity Questions: Howell signals that lower courts will treat Chiaverini as forward-looking only. Pending malicious-prosecution suits rooted in pre-2024 conduct will likely be dismissed on qualified-immunity grounds.
Emphasis on Out-of-Circuit Authority: Litigants must now survey national case law, not merely Sixth Circuit precedent, to assess whether a right is “clearly established.”

Complex Concepts Simplified

Qualified Immunity: A legal shield protecting officials from damages unless both a constitutional violation occurred and existing case law would have made every reasonable officer know the act was unlawful.
Exigent Circumstances: Situations so urgent (e.g., threat to life, destruction of evidence) that officers may bypass the normal requirement of a search warrant.
Probable Cause vs. Proof Beyond Reasonable Doubt: Probable cause is only a “substantial chance” of criminal activity—far less than the certainty needed to convict at trial.
Monell Liability: Municipalities are not liable for isolated officer misconduct; plaintiffs must show an explicit policy or an entrenched, widespread custom that caused the violation.
Malicious Prosecution (Post-Thompson): A Fourth Amendment claim requiring (1) officer’s role in prosecution, (2) lack of probable cause, (3) post-arrest deprivation of liberty, and (4) favorable termination of the case.

Conclusion

The Sixth Circuit’s decision in Howell v. McCormick underscores the judiciary’s increasing insistence on nuanced, fact-specific precedent before stripping officers of qualified immunity. By crystallising the “odor-plus-awareness” scenario and grounding the analysis in a broad survey of sister-circuit opinions, the court created the Howell Rule: unless and until precedent squarely forbids warrantless entry under similar circumstances, officers remain protected. The ruling also:

Reaffirms the sufficiency of uncontradicted eyewitness testimony for probable cause,
Clarifies that Chiaverini cannot retroactively unsettle settled immunity, and
Confirms that vague or isolated examples will not sustain Monell liability.

Going forward, civil-rights practitioners must marshal highly specific, on-point authority— ideally from within the circuit—to surmount qualified immunity, particularly in exigent-circumstance home-entry cases. Municipalities, meanwhile, are encouraged to review and codify policies that explicitly incorporate constitutional standards, thereby insulating themselves from “policy or custom” attacks. Ultimately, Howell reflects the Sixth Circuit’s continued deference to law-enforcement decision-making in rapidly evolving, ambiguous situations, while still leaving room for liability once the law crystallises.