Mitigating-Role Reductions Require a Full “Relevant Conduct” Comparator Universe and an On-the-Record Guía-Sendeme Analysis

1. Introduction

In United States v. Robles-López (1st Cir. Feb. 3, 2026), the First Circuit vacated a 48-month sentence imposed on Crystall Kareem Robles-López after concluding the district court committed a legal error in denying a mitigating-role adjustment under U.S.S.G. § 3B1.2. Robles had agreed to fly from San Juan, Puerto Rico to Newark, New Jersey with two suitcases later found to contain approximately eleven kilograms of cocaine. Although the U.S. Probation Office recommended a three-level mitigating-role reduction, the district court sustained the government’s objection and denied the reduction.

The central issue on appeal was procedural: whether the district court properly performed the required comparative culpability analysis—i.e., whether Robles was “substantially less culpable than the average participant in the criminal activity.” A second threshold issue was preservation: whether Robles’s objections at sentencing were specific enough to secure abuse-of-discretion review rather than plain-error review.

2. Summary of the Opinion

The First Circuit held that Robles preserved her procedural challenge and therefore received abuse-of-discretion review, with de novo review of legal questions concerning the Guidelines’ interpretation and application.

On the merits, the panel ruled that the district court failed to perform the correct mitigating-role analysis. Specifically, the sentencing judge:

  • Improperly narrowed the “universe of participants” to Robles’s acts at the airport, rather than considering all participants involved in the relevant conduct of the single drug shipment (including preparatory steps);
  • Failed to conduct the structured comparative culpability inquiry recently clarified in United States v. Guía-Sendeme, 134 F.4th 611 (1st Cir. 2025);
  • Placed inappropriate weight on “indispensability” and treated expected payment as a negative factor contrary to § 3B1.2 commentary.

The court vacated the sentence and remanded for resentencing so the district court could apply the correct four-part Guía-Sendeme framework and evaluate the § 3B1.2 factors on a proper comparator set.

3. Analysis

3.1. Precedents Cited

A. The controlling role-reduction framework

United States v. Guía-Sendeme, 134 F.4th 611 (1st Cir. 2025) is the opinion’s doctrinal anchor. Guía-Sendeme distilled a four-part method for deciding § 3B1.2 eligibility: (1) identify the universe of participants in the relevant criminal activity; (2) order participants along a culpability continuum; (3) identify the average participant; and (4) compare the defendant to that average. Robles-López treats that framework as mandatory “correct analysis,” and faults the district court for the same category of error: misidentifying the comparator universe and substituting guilt-recitation for culpability comparison.

United States v. Guzmán-Ceballos, 144 F.4th 1 (1st Cir. 2025) supplied the panel’s operative legal standard: “The district court commits reversible legal error when it fails to perform the correct mitigating role analysis.” Robles-López applies that principle directly, describing the district court’s approach as the same type of legal failure that required remand in Guzmán-Ceballos.

United States v. Flores-Álvarez, No. 23-1163, 2025 WL 1369300 (1st Cir. May 12, 2025) (unpublished) is significant because it involved an aviation smuggling fact pattern closer to Robles’s than the maritime cases. Robles-López uses it to reinforce the proposition that focusing only on the defendant’s physical acts at the airport (or on the boat) is inadequate when there is record evidence of others who planned, supplied, recruited, or were positioned to receive the shipment.

B. Correctly reading earlier First Circuit precedent

The district court relied on United States v. Arias-Mercedes, 901 F.3d 1 (1st Cir. 2018) to limit the inquiry to Robles’s conduct in the airport. Robles-López, following Guía-Sendeme, explains that this is a misreading: the “voyage”/single-transaction focus in Arias-Mercedes limits the inquiry to the defendant’s personally-involved shipment, but does not license ignoring other discernible participants who prepared and executed that shipment. The “average participant” is not “hypothetical”; it must be built from the actual likely participants in the relevant criminal activity.

United States v. Walker, 89 F.4th 173 (1st Cir. 2023) plays two roles: (i) it supplies the general taxonomy (minimal/minor/between) and emphasizes the need for a comparative assessment, and (ii) it underscores that “integral” participation is not the legal standard—echoing § 3B1.2’s commentary that “essential or indispensable” is not determinative. Robles-López cites Walker to mark the district court’s “indispensability” emphasis as a legal misstep.

The opinion also invokes United States v. Quinones-Medina, 553 F.3d 19 (1st Cir. 2009) (and United States v. Jurado-Lopez, 338 F. Supp. 2d 246 (D. Mass. 2004)) to clarify a common misconception: “drug mule” status is not a talisman. A courier can be fringe or central; the Guidelines require a fact-based, comparative culpability analysis rather than categorical assumptions.

C. Persuasive authority from other circuits

Although not controlling, the opinion notes parallel structuring efforts in the Ninth Circuit: United States v. Chichande, 113 F.4th 913 (9th Cir. 2024) and United States v. Dominguez-Caicedo, 40 F.4th 938 (9th Cir. 2022). This cross-circuit discussion supports the First Circuit’s insistence that role determinations must be grounded in identifying participants and comparing culpability to an empirically derived “rough average,” not by relying on conclusory labels or a narrow snapshot of the defendant’s acts.

The panel also cites Tenth Circuit cases—United States v. Nkome, 987 F.3d 1262 (10th Cir. 2021) and United States v. Yurek, 925 F.3d 423 (10th Cir. 2019)—for the central theme that § 3B1.2 turns on “relative culpability.” These citations reinforce that the inquiry is comparative by design and not merely descriptive of the defendant’s own acts.

D. Standard-of-review and preservation precedents

On preservation, the court synthesizes multiple First Circuit decisions: United States v. Reyes-Correa, 81 F.4th 1 (1st Cir. 2023), United States v. Soto-Soto, 855 F.3d 445 (1st Cir. 2017), United States v. Colón-Cordero, 91 F.4th 41 (1st Cir. 2024), United States v. Ahrendt, 560 F.3d 69 (1st Cir. 2009), and United States v. Rivera-Berríos, 968 F.3d 130 (1st Cir. 2020). The key takeaway is functional notice: objections must be specific enough to alert the sentencing court to the claimed error, but need not be “exquisite.” Robles preserved by repeatedly objecting to the role-reduction analysis, urging adoption of the PSR’s comparator-based approach, and incorporating her written submissions.

The government’s attempt to force plain-error review relied on United States v. Fígaro-Benjamín, 100 F.4th 294 (1st Cir. 2024) and United States v. Pabon, 819 F.3d 26 (1st Cir. 2016), but those cases did not control because the panel found preservation satisfied.

Finally, the panel cites United States v. Quirós-Morales, 83 F.4th 79 (1st Cir. 2023) for the proposition that legal error constitutes abuse of discretion, and Gall v. United States, 552 U.S. 38 (2007) for the requirement of sufficient explanation to permit meaningful appellate review.

E. Relevant-conduct boundaries

The opinion uses United States v. Walton, 908 F.2d 1289 (6th Cir. 1990) (cited within Arias-Mercedes) to illustrate the conceptual boundary: a defendant held responsible for a specific distribution episode should not be compared to actors in an entire broader conspiracy beyond that episode. Robles-López stresses, however, that “single shipment” limitation still includes those who prepared, coordinated, supplied, and planned that shipment.

3.2. Legal Reasoning

A. The comparator-universe error: narrowing “relevant conduct” to the defendant’s visible acts

Robles-López identifies the district court’s threshold mistake as collapsing the relevant conduct into only what Robles did at the airport—accepting luggage, checking it, and intending to fly. Under Guía-Sendeme, the first step is identifying the universe of participants “in the relevant criminal activity.” That necessarily requires determining “relevant conduct as a whole,” including actions undertaken “in preparation for that offense” or in attempts to avoid detection (incorporating U.S.S.G. § 1B1.3(a)(1)(B) language quoted in Guía-Sendeme).

Here, the PSR identified multiple other participants: two recruiters, an organizer, and an unknown man who transported Robles, supplied the suitcases, and orchestrated her movements—including bypassing USDA screening using pre-affixed stickers. By refusing to include those discernible actors in the comparator set, the district court ensured the “average participant” would effectively be Robles herself, making a mitigating role finding structurally impossible.

B. The analytic-method error: reciting guilt rather than comparing culpability

The panel also faults the district court for failing to engage the five § 3B1.2 commentary factors as comparative tools. Instead, the court used them to restate why Robles was guilty (she agreed, acted, expected payment). Robles-López emphasizes that the § 3B1.2 factors are not an elements-of-the-offense checklist; they exist to determine whether leniency is warranted because the defendant’s role was “substantially subordinate” within the criminal activity.

C. The “indispensability” and payment errors

Robles-López highlights two related misapplications:

  • Indispensability is not determinative: The district court’s reliance on Robles’s necessary function as the courier conflicts with the commentary to U.S.S.G. § 3B1.2 cmt. n.3(C) and with Walker, which rejects “integral role” as the legal test.
  • Expected payment is not a per se disqualifier and must be contextualized: The Guidelines expressly direct that a person “simply being paid to perform certain tasks” should be considered for an adjustment, and that essentiality is not determinative. The court’s negative use of her expected payment departed from that instruction, especially where the record suggested a small fraction of drug value and no proprietary stake.

D. Preservation and procedural fairness

The preservation holding is practically important. The panel treats the objection as preserved despite the lack of “exquisite precision,” recognizing that counsel explicitly contested the court’s approach, invoked the PSR’s comparator-based reasoning, and incorporated the written memorandum. This reinforces that defendants need not use formulaic language to preserve a Guidelines-methodology error; what matters is whether the district judge was alerted to the specific procedural flaw.

E. A notable admonition about record fidelity

Robles-López includes an unusually pointed passage criticizing the government’s appellate portrayal of Robles as “the star of the show,” identifying assertions “patently inconsistent” with the undisputed record (e.g., claims she arranged her own transport or exercised sophisticated discretion). While not framed as a sanctionable finding, the passage signals that, in role-reduction litigation, appellate courts may scrutinize whether the parties’ culpability narratives are anchored to PSR facts and sentencing-record admissions.

3.3. Impact

Robles-López solidifies (and operationalizes) the Guía-Sendeme line in three ways likely to affect future sentencing proceedings:

  • Drug-courier cases (airport, maritime, or otherwise) must treat preparatory actors as comparators when supported by record evidence—recruiters, organizers, loaders, transporters, lookouts, and intended recipients can fall within the “universe of participants” for the single shipment.
  • District courts must make the comparative analysis traceable on the record. Even if the ultimate decision is discretionary and fact-bound, failure to follow the structured steps (universe → continuum → average → comparison), guided by the five factors, is reversible legal error.
  • “Indispensability” arguments weaken as categorical objections. Prosecutorial claims that a courier is indispensable will not defeat § 3B1.2 absent a genuine comparison showing the courier is not substantially less culpable than the shipment’s average participant.

A practical consequence—visible in this case—is that role-reduction errors can matter even after custodial time is served, because supervised release terms and conditions may be revisited on remand and because the Guidelines range influences the entire sentencing architecture.

4. Complex Concepts Simplified

  • Mitigating-role adjustment (U.S.S.G. § 3B1.2): A Guidelines reduction (2 to 4 levels) for defendants who played a smaller part in the criminal activity than most others involved.
  • “Average participant”: Not an imaginary person in a generic conspiracy. It is the midpoint of culpability among the actual likely participants in the defendant’s relevant criminal activity.
  • “Relevant conduct”: The set of acts and actors the sentencing court may consider for Guidelines purposes—often broader than the defendant’s own hands-on acts and can include preparation and avoidance efforts.
  • “Indispensable” role: Being necessary for the crime to succeed does not automatically make a defendant more culpable; the Guidelines say essentiality is “not determinative.”
  • Preservation vs. plain error: If a defendant adequately objected in the district court, the appellate court reviews under abuse of discretion (more favorable to the defendant). If not preserved, review is only for plain error (harder to win).
  • Downward variance: A sentence below the advisory Guidelines range based on statutory sentencing factors (even if the Guidelines calculation is unchanged).

5. Conclusion

United States v. Robles-López applies and extends the First Circuit’s recent clarification that § 3B1.2 is a structured, comparative inquiry. The opinion’s core lesson is methodological: sentencing courts must identify all discernible participants in the single-shipment “relevant conduct,” use the § 3B1.2 factors to place them on a culpability spectrum, identify the average participant, and then compare the defendant to that average. A court that instead narrows the universe to the defendant’s visible acts, relies on “indispensability,” or recites guilt rather than comparing culpability commits reversible legal error.