Independent Traffic Violation and Attenuation Cure an Earlier Unlawful Prolongation; Redundant Records Checks During Ongoing Citation Work Do Not “Prolong” a Stop

Case: United States v. Robert Pennington, Jr. (7th Cir. Sept. 4, 2026)

Panel: Sykes, Hamilton, Pryor, Circuit Judges (Hamilton, J., dissenting)

1) Introduction

In United States v. Robert Pennington, Jr., the Seventh Circuit addressed a recurring Fourth Amendment pattern: a first traffic stop ends without a search, the officer communicates suspicion to a second officer up the road, and a second stop ultimately produces a canine sniff and contraband.

Pennington (the defendant-appellant) was stopped twice in less than two hours on I-57 in Illinois. Master Sergeant Mark Flack conducted the first stop for speeding, issued a warning, and then continued drug-focused questioning after completing the stop’s “mission.” Sergeant John Lillard (a canine officer) later stopped Pennington again after observing a new traffic infraction and conducted a dog sniff that led to discovery of crack cocaine. Pennington sought suppression of the drugs and dismissal of the indictment, alleging (selectively) that he was targeted for exercising constitutional rights.

Key issues:

  • Whether either traffic stop was unlawfully prolonged under Rodriguez v. United States.
  • If the first stop was unlawful, whether the drugs found in the second stop were suppressible as “fruit of the poisonous tree,” or instead admissible under attenuation principles.
  • Whether Pennington was entitled to an evidentiary hearing on a selective enforcement claim.

2) Summary of the Opinion

The court affirmed across the board:

  • First stop: The panel held Sergeant Flack did unlawfully prolong the stop by continuing to interrogate Pennington about drugs after issuing the warning and returning documents. However, suppression of drugs found later was not warranted because the later discovery was sufficiently attenuated from this illegality.
  • Second stop: The panel held Sergeant Lillard did not unlawfully prolong the second stop; the dog sniff occurred while the traffic warning was still being processed, and delays were attributable to computer problems rather than purposeful extension.
  • Selective enforcement: The panel held Pennington failed to make a prima facie showing sufficient to justify an evidentiary hearing; an independently observed traffic violation defeated the needed showing of discriminatory purpose “in his case.”

3) Analysis

A. Precedents Cited

i. The “mission” of a traffic stop and the anti-prolongation rule

  • Rodriguez v. United States, 575 U.S. 348 (2015): The foundation. The panel used Rodriguez to define the stop’s “mission” and to hold that authority for the seizure ends when that mission “is—or reasonably should have been—completed.” It also relied on Rodriguez to reject any “de minimis” extension rationale for unrelated tasks, while still permitting unrelated tasks (like a dog sniff) if they do not add time.
  • United States v. Rodriguez-Escalera, 884 F.3d 661 (7th Cir. 2018): Cited for the Seventh Circuit’s application of Rodriguez: absent reasonable suspicion, a dog sniff or similar measure may not extend the stop.
  • United States v. Cole, 21 F.4th 421 (7th Cir. 2021) (en banc): Supplied the Seventh Circuit’s post-Rodriguez framework: a stop must be justified at inception and reasonably related in scope; unrelated questioning is allowed only if it does not prolong the stop.
  • Illinois v. Caballes, 543 U.S. 405 (2005): Confirmed that a dog sniff is not itself part of the “mission,” but can occur during a lawful stop without Fourth Amendment violation if it does not prolong the stop.
  • Arizona v. Johnson, 555 U.S. 323 (2009): Supported the proposition that unrelated questioning during a stop is permissible so long as it does not measurably extend the detention.
  • Hiibel v. Sixth Jud. Dist. Ct. of Nev., 542 U.S. 177 (2004): Provided the general “inception and scope” formulation used for traffic-stop reasonableness.

ii. What counts as ordinary inquiries and safety precautions

  • United States v. Devalois, 128 F.4th 894 (7th Cir. 2025): Used repeatedly to describe permissible “ordinary inquiries,” to emphasize the endpoint of seizure authority, and to approve task-sharing (“transfer of duties”) so long as it does not prolong the stop.
  • United States v. Gholston, 1 F.4th 492 (7th Cir. 2021): Applied as a standard of review touchstone (clear-error review of district court’s “no prolongation” finding) and as a model for affirming despite a district court’s “imperfect language” about “de minimis” delay if the substantive finding is that there was no extension.
  • United States v. Goodwill, 24 F.4th 612 (7th Cir. 2022) and United States v. Lewis, 920 F.3d 483 (7th Cir. 2019): Cited for the permissibility of having a driver sit in the squad car as reasonably incidental to the stop and for the governing rule on dog sniffs (no prolongation absent independent suspicion).
  • United States v. Simon, 937 F.3d 820 (7th Cir. 2019) (quoting Swanigan v. City of Chicago, 881 F.3d 577 (7th Cir. 2018)) and United States v. Sanford, 806 F.3d 954 (7th Cir. 2015): Supported the panel’s view that warrant/driving/criminal-history checks are routine and justified by officer safety—even without separate reasonable suspicion—and may be done during the stop.

iii. Pretext, probable cause/reasonable suspicion, and independent traffic violations

  • United States v. Avila, 106 F.4th 684 (7th Cir. 2024): Used for standards of review and for the proposition that routine traffic stops require reasonable suspicion of a traffic violation.
  • United States v. Jackson, 962 F.3d 353 (7th Cir. 2020): Cited to reinforce that even minor traffic violations can justify a stop.
  • Whren v. United States, 517 U.S. 806 (1996) and United States v. Bass, 325 F.3d 847 (7th Cir. 2003): Supported the panel’s key move that subjective motives (including drug-interdiction interest or awareness of prior refusal) do not invalidate an objectively justified traffic stop.

iv. When a stop becomes consensual—or not

  • United States v. Finke, 85 F.3d 1275 (7th Cir. 1996): “Retention or return of documentation is not dispositive” on whether the seizure has ended.
  • United States v. Lopez, 907 F.3d 472 (7th Cir. 2018) and United States v. Drayton, 536 U.S. 194 (2002): Framed the “totality of circumstances” test: whether a reasonable person would feel free to terminate the encounter.
  • United States v. Borys, 766 F.2d 304 (7th Cir. 1985) and United States v. Smith, 794 F.3d 681 (7th Cir. 2015): Used to show why continued drug-accusatory questioning in a controlled or enclosed environment tends not to be consensual.

v. Fruit of the poisonous tree and attenuation

  • Utah v. Strieff, 579 U.S. 232 (2016): Provided the modern articulation of attenuation and its three-factor framework (via Brown), and reinforced that suppression is reserved for situations where deterrence benefits outweigh social costs.
  • Brown v. Illinois, 422 U.S. 590 (1975): The three-factor attenuation analysis: temporal proximity, intervening circumstances, and purpose/flagrancy.
  • Wong Sun v. United States, 371 U.S. 471 (1963) and United States v. Green, 111 F.3d 515 (7th Cir. 1997): Supplied the “exploitation” vs. “purged of the primary taint” formulation.
  • Hudson v. Michigan, 547 U.S. 586 (2006): Cited for the principle that suppression is a “last resort.”
  • United States v. McGill, 8 F.4th 617 (7th Cir. 2021) and United States v. Davis, 44 F.4th 685 (7th Cir. 2022): Used to frame the exclusionary rule’s cost-benefit logic and to apply attenuation (including the relevance of “bad faith” and deterrence).
  • Davis v. United States, 564 U.S. 229 (2011): Invoked to emphasize that suppression is inappropriate where it would do nothing to deter misconduct.

vi. Selective enforcement and evidentiary hearings

  • Conley v. United States, 5 F.4th 781 (7th Cir. 2021): Set the two elements for selective enforcement: discriminatory effect and discriminatory purpose, with the insistence on purpose “in his case.”
  • United States v. Kerley, 787 F.2d 1147 (7th Cir. 1986) (per curiam): Provided the threshold to obtain an evidentiary hearing: a prima facie showing raising a “reasonable doubt” about improper purpose.
  • McCleskey v. Kemp, 481 U.S. 279 (1987): Used (via Conley) to require discriminatory purpose as to the particular defendant, not general statistical disparities alone.
  • Bolling v. Sharpe, 347 U.S. 497 (1954): Cited for reverse incorporation: equal protection principles apply to federal action via the Fifth Amendment.
  • United States v. Skoczen, 405 F.3d 537 (7th Cir. 2005) and United States v. Curlin, 638 F.3d 562 (7th Cir. 2011): Supplied standards of review for dismissal and evidentiary-hearing denials.

vii. Persuasive authority and the dissent

  • United States v. Gorman, 859 F.3d 706 (9th Cir. 2017): The majority distinguished Gorman, rejecting the idea that coordination plus suspicion “significantly directed” the later stop where the second officer independently observed a new traffic violation. The dissent, by contrast, treated Gorman as closely analogous and urged evaluating the stops as a coordinated whole.
  • The dissent also cited United States v. Foreste, 780 F.3d 518 (2d Cir. 2015) and United States v. Ilazi, 730 F.2d 1120 (8th Cir. 1984) to warn against “gamesmanship” via successive stops.

B. Legal Reasoning

i. The first stop was unlawfully prolonged, and it was not “consensual”

The panel held the first stop’s lawful mission ended once Sergeant Flack printed the warning, explained it, and returned Pennington’s documents. Continuing to interrogate about drugs and seek consent to search for roughly three more minutes—without independent reasonable suspicion—violated Rodriguez.

The government argued the encounter became consensual once documents were returned. Relying on United States v. Finke, United States v. Lopez, and United States v. Drayton, the panel rejected this: the setting (inside the officer-controlled squad car), the accusatory drug-focused questioning, and Pennington’s unanswered inquiry about whether he could leave meant a reasonable person would not feel free to terminate the encounter.

ii. But the unlawful first stop did not require suppression of drugs found later: attenuation

The crucial move in the opinion is that the illegality in the first stop did not automatically taint the second stop’s evidence. Applying attenuation principles from Utah v. Strieff and Brown v. Illinois, the panel held the causal chain was sufficiently broken.

  • Temporal proximity: About an hour passed between the first stop’s unlawful prolongation and the second stop. The panel treated that as “substantial time” supporting attenuation (analogizing to United States v. Davis, 44 F.4th 685).
  • Intervening circumstance: Sergeant Lillard independently observed a new traffic infraction (improper lane usage). That new violation—objectively supporting a stop under United States v. Jackson—was deemed an intervening event severing the causal link.
  • Purpose and flagrancy: Although Sergeant Flack’s conduct was unlawful, the panel found no “systemic or recurrent police misconduct” and emphasized that Sergeant Lillard’s subsequent conduct was lawful. Suppression would therefore yield minimal deterrent benefit under Davis v. United States.

This portion of the decision effectively establishes (at least within the Seventh Circuit’s existing doctrine) that when an officer unlawfully prolongs a first stop, a later stop that is objectively justified by a newly observed traffic violation will often be treated as sufficiently distinguishable—despite officer-to-officer communication—unless the later stop is itself exploitative or otherwise unlawful.

iii. The second stop was not “prolonged,” even with redundant checks and a dog sniff

Pennington challenged the second stop by arguing it was extended to enable a canine sniff and that certain tasks were redundant because Sergeant Flack had already run checks. The panel rejected both lines of attack on two related grounds:

  • Ordinary inquiries and safety measures remained permissible: The panel held Sergeant Lillard could have Pennington sit in the squad car (United States v. Goodwill; United States v. Lewis), ask about weapons as a safety precaution, and run record checks and criminal-history checks as routine safety-related inquiries (United States v. Simon; United States v. Sanford). Importantly, the court declined to impose a rule requiring the second officer to rely on the first officer’s checks.
  • No added time attributable to the sniff or task-switching: Applying Rodriguez and reviewing for clear error (with guidance from United States v. Gholston), the panel accepted the district court’s finding that the dog sniff occurred while the written warning was still being prepared and before it was issued. Computer/login problems explained delay, and swapping duties with Trooper Dorsey did not itself prolong the stop (United States v. Devalois).

The dissent sharply disagreed, characterizing the records checks as “redundant” and effectively “enabling” the sniff, and urged adopting the Ninth Circuit’s approach in United States v. Gorman. The majority’s response was to treat “redundancy” as constitutionally irrelevant so long as the officer is still diligently pursuing the traffic mission and the dog sniff does not add time.

iv. Selective enforcement: no evidentiary hearing without a prima facie showing of discriminatory purpose

Pennington framed selective enforcement as retaliation for exercising his right to refuse consent to search. The panel assumed that exercising constitutional rights can be a “protected characteristic” (citing United States v. Kerley), but held Pennington failed to meet the prima facie threshold:

  • He did not contest that Sergeant Lillard independently observed a traffic violation.
  • He did not identify similarly situated drivers treated differently.
  • He did not show Lillard stopped him “because of” (not merely “in spite of”) his rights-exercise, as required by Conley v. United States.

Accordingly, the denial of an evidentiary hearing was not an abuse of discretion.

C. Impact

  • Sequential-stop suppression claims face a higher practical hurdle: The opinion provides a road map for admitting evidence obtained in a second stop even when a first stop was unlawfully prolonged, particularly where the second stop is supported by an intervening, independently observed traffic violation.
  • “Redundant checks” are not necessarily “prolongation” in the Seventh Circuit: The court’s approach suggests that repetition of license/warrant/criminal-history inquiries by a second officer is not inherently problematic; the constitutional question remains whether the traffic mission was delayed, not whether the inquiries were necessary given earlier checks.
  • Rodriguez litigation will likely pivot to timing proof and diligence: Because the majority’s analysis turns on whether the dog sniff added time, future cases may focus even more on video timing, computer logs, and whether the officer was diligently pursuing the citation/warning tasks (as opposed to using them as a pretextual clock).
  • Selective enforcement claims remain difficult without comparators: The decision reinforces that alleging improper motive (even when plausible) is not enough to obtain a hearing absent facts showing discriminatory purpose and differential treatment of similarly situated individuals.

4) Complex Concepts Simplified

  • “Mission” of the stop: The legitimate tasks tied to the traffic violation and safety (e.g., checking license, warrants, registration, insurance; explaining the violation; writing the warning/citation).
  • “Prolongation”: Any added time beyond what is reasonably needed to complete the mission. Under Rodriguez, even small extensions can be unlawful if they are attributable to unrelated investigations (like drug dog sniffs) without independent reasonable suspicion.
  • “Consensual encounter” after a stop: After the mission ends, police may still talk to a person, but only if a reasonable person would feel free to leave. Being inside a squad car, facing accusatory questioning, or being physically/psychologically constrained often means it is not truly consensual.
  • “Fruit of the poisonous tree” and “attenuation”: Evidence found after illegal police conduct can be suppressed if it was obtained by exploiting that illegality. But if an intervening event breaks the causal chain—like a new, independently observed traffic violation—courts may deem the connection attenuated and admit the evidence.
  • Selective enforcement (equal protection): Requires proof of both discriminatory effect (others similarly situated were treated differently) and discriminatory purpose (the officer acted because of the protected characteristic).

5) Conclusion

United States v. Robert Pennington, Jr. delivers a split message with a unifying theme: Rodriguez limits are real, but suppression is not automatic. The Seventh Circuit held the first stop was unlawfully prolonged after its mission ended, yet refused suppression because the second stop was justified by an intervening, independently observed traffic violation and the later discovery of evidence was deemed attenuated. It also held that routine safety-related checks and a dog sniff are permissible when they do not add time to the traffic mission, even if some tasks appear redundant in a coordinated two-stop sequence. Finally, the court reaffirmed that selective enforcement claims require a concrete prima facie showing—particularly comparator evidence and purpose “in his case”—to warrant an evidentiary hearing.