Defining the Universe of Participants for Mitigating Role Adjustments in Maritime Narcotics Transport

Introduction

United States v. Guía-Sendeme, 23-1162 (1st Cir. Apr. 18, 2025), confronts the proper application of two provisions in the United States Sentencing Guidelines (U.S.S.G.) during sentencing for maritime cocaine smuggling. Defendant Dionel Guía-Sendeme pleaded guilty to importing and possessing with intent to distribute over five kilograms of cocaine after piloting a small vessel from the Dominican Republic to Puerto Rico.

At sentencing, the District of Puerto Rico calculated a Guidelines range of 108–135 months, applying a two-level firearm enhancement (U.S.S.G. § 2D1.1(b)(1)) and denying any mitigating role reduction (U.S.S.G. § 3B1.2). The district court imposed a downward variance to 72 months. On appeal, Guía argued that the court mis­applied both enhancements and adjustments; the First Circuit affirmed the firearm enhancement but remanded for reconsideration of the mitigating role analysis.

Summary of the Judgment

The First Circuit held that:

• Firearm Enhancement: Guía conceded he saw a coconspirator receive and carry a handgun immediately before the voyage. That admission alone sufficed to trigger U.S.S.G. § 2D1.1(b)(1), without a separate finding of foreseeability.
• Mitigating Role Adjustment: The district court erred by restricting its § 3B1.2 analysis to the two crewmembers aboard the boat, rather than all participants involved in the same shipment under U.S.S.G. § 1B1.3. It also failed to compare Guía’s culpability against that broader universe using the five non-exhaustive § 3B1.2 factors.
• Accordingly, the case is remanded for resentencing to permit a full, correct analysis of whether Guía played a minor or minimal role in the venture.

Analysis

1. Precedents Cited

• United States v. Vargas, 560 F.3d 45 (1st Cir. 2009): Held that “relevant conduct” under U.S.S.G. § 1B1.3 encompasses all acts in furtherance of the jointly undertaken criminal activity that are reasonably foreseeable, not just the elements recited in the indictment.
• United States v. Arias-Mercedes, 901 F.3d 1 (1st Cir. 2018): Clarified that in single-shipment maritime cases, relevant conduct is limited to that shipment, but the universe of participants must include all individuals who substantially contributed to it.
• United States v. Castillo, 995 F.3d 14 (1st Cir. 2021): Applied Arias-Mercedes to affirm denial of a § 3B1.2 reduction when the record contained no evidence of other participants outside the three vessel operators.
• United States v. Walker, 89 F.4th 173 (1st Cir. 2023): Reiterated the four-step process for § 3B1.2 (identify the universe of participants; rank them on a culpability continuum; locate the average participant; compare the defendant to that average using the five factors).

2. Legal Reasoning

a. Scope of Relevant Conduct and Universe of Participants

Under U.S.S.G. § 1B1.3(a)(1)(B), a defendant’s relevant conduct in a conspiracy case includes all acts in furtherance of the jointly undertaken criminal activity that were reasonably foreseeable. When the base offense level is driven by a single drug shipment, “relevant conduct” is that shipment alone—but “all participants” in that shipment must be counted, not solely those on the boat at the moment of arrest.

The district court limited its § 3B1.2 inquiry to the two crew members aboard the vessel, excluding recruiters, loaders, look-outs, and other helpers. The First Circuit held this contravened both Vargas and Arias-Mercedes, which require sentencing courts to canvass the full roster of individuals who unquestionably played roles in the same voyage.

b. The Four-Step § 3B1.2 Process

1. Identify the universe of participants in the relevant conduct (the single maritime shipment).
2. Rank participants on a culpability continuum (from masterminds and organizers down to minors and bystanders).
3. Pinpoint the “average participant.”
4. Compare the defendant’s role to the average using the five § 3B1.2(c)(3)(C) factors:
   • Knowledge of the scope and structure of the activity
   • Participation in planning or organizing
   • Decision-making authority or influence
   • Nature, extent, and discretion in performing tasks
   • Degree of benefit from the activity

The district court only recited two factors superficially and did not locate an “average participant” against which Guía’s role could be compared. The First Circuit deemed that an abuse of discretion requiring remand.

c. Firearm Enhancement under § 2D1.1(b)(1)

An enhancement applies if a firearm was possessed during the offense by the defendant or a coconspirator, provided possession was not “clearly improbable.” Here, Guía admitted on the stand that he watched his coconspirator receive a handgun before departure. That admission satisfied knowledge, so no separate foreseeability finding was needed. The First Circuit therefore upheld the two-level enhancement.

3. Impact on Future Cases

This decision clarifies sentencing practice in maritime drug-trafficking prosecutions:

• Courts must cast a wide net in identifying every individual who had a concrete role in the specific voyage that generates the base offense level.
• A full § 3B1.2 analysis requires locating an “average participant” and comparing a defendant’s role to that benchmark via all five Guideline factors.
• Defendants in large or complex smuggling operations may have stronger grounds for a mitigating role adjustment if their tasks were routine, discrete, and less central than average.

Complex Concepts Simplified

• Relevant Conduct (U.S.S.G. § 1B1.3): Everything the defendant did or foresaw in furtherance of the crime counted for Guidelines purposes—even if not charged in the indictment—but limited to the single shipment when that controls the base offense level.
• Mitigating Role Adjustment (U.S.S.G. § 3B1.2): A 2- to 4-level decrease if you were less at fault than most participants—think “lab tech” versus “mastermind.” You must prove it by comparing your actual tasks to those of everyone else in the same shipment.
• Firearm Enhancement (U.S.S.G. § 2D1.1(b)(1)): Adds 2 levels if a gun was present during your drug crime. A confession that you saw a co-participant with a gun will do.

Conclusion

United States v. Guía-Sendeme reaffirms that district courts must adhere to the Sentencing Guidelines’ detailed instructions when granting or denying role-based adjustments. By requiring a comprehensive, fact-specific identification of all participants and a structured comparison under § 3B1.2, the First Circuit ensures that defendants receive fair, proportionate sentences reflecting their true blameworthiness. The case also confirms that a candid admission of seeing a “buddy” carry a firearm suffices for the two-level weapons enhancement under § 2D1.1(b)(1).

Sentencers in maritime narcotics cases should therefore:

• Chart every individual’s involvement in the lone drug shipment at issue.
• Use the five Guideline factors to see if the defendant was substantially less culpable than the “average” participant.
• Apply firearm enhancements where knowledge of a coconspirator’s weapon is uncontested.

This structured approach promotes consistency, transparency, and proportionality in federal drug-trafficking sentencing.