United States v. Rosario-Sánchez: The First Circuit Re-Affirms the “Apples-to-Apples” Standard for Co-Defendant Sentencing-Disparity Claims

1. Introduction

The First Circuit’s decision in United States v. Rosario-Sánchez, No. 22-1857 (1st Cir. 2025), stems from a brutal ten-day crime spree in Puerto Rico that left four people dead and several others injured. The defendant, Nycole Amaury Rosario-Sánchez (“Rosario”), was only 15 years old at the time but agreed to be prosecuted as an adult. After pleading guilty to a six-count information—including Hobbs-Act robberies, carjackings, and a § 924(j)(1) firearm/murder charge—Rosario received a 480-month (40-year) sentence.

On appeal, he challenged the sentence as both procedurally and substantively unreasonable, asserting that the district court (i) neglected to weigh fully his difficult childhood and intellectual limitations, and (ii) failed to address an alleged unwarranted disparity between his sentence and the lower sentences imposed on his adult co-defendants.

The First Circuit affirmed. While the opinion covers familiar terrain—procedural and substantive reasonableness review—the panel crystallises and re-emphasises a key point: a defendant alleging an unwarranted co-defendant disparity must offer a genuine “apples-to-apples” comparison supported by record evidence. Absent that, the claim fails—even where, as here, the challenger received the harshest sentence of the group.

2. Summary of the Judgment

• Procedural reasonableness: The panel found no abuse of discretion. The district court explicitly noted its consideration of the § 3553(a) factors—Rosario’s age, mental health, and troubled upbringing—and explained why those factors did not justify the 240-month sentence he requested.
• Sentencing-disparity argument: Rosario failed to provide the information necessary to establish that he and his co-defendants were truly comparable. Material differences—different judges, different roles, different plea agreements, and incomplete sentencing data at the time—defeated the claim.
• Substantive reasonableness: A downward variance from life to 40 years carried a presumption of reasonableness. Given the extraordinarily violent nature of the offenses and Rosario’s threats while incarcerated, the 480-month sentence was deemed defensible.
• Collateral arguments (Miller, Atkins, cumulative error): The panel rejected each as either unpreserved, inapposite, or undeveloped.
• Disposition: Sentence AFFIRMED.

3. Analysis

3.1 Precedents Cited and Their Influence

• United States v. Reyes-Santiago, 804 F.3d 453 (1st Cir. 2015) — coined the “apples-to-apples” phrase for disparity claims; reiterated that § 3553(a)(6) is aimed primarily at national, not intra-case, disparities.
• United States v. Demers, 842 F.3d 8 (1st Cir. 2016) — held that material differences between a defendant and comparators will doom a disparity argument.
• Gall v. United States, 552 U.S. 38 (2007) — established the bifurcated appellate review (procedural first, then substantive) and the abuse-of-discretion standard.
• Miller v. Alabama, 567 U.S. 460 (2012) — invalidated mandatory life-without-parole for juveniles; Rosario invoked it, but the First Circuit noted that Miller does not apply to non-mandatory, term-of-years sentences.
• Atkins v. Virginia, 536 U.S. 304 (2002) — barred execution of intellectually disabled offenders; cited by Rosario as to diminished culpability, but argument deemed waived/undeveloped.
• Multiple First Circuit sentencing cases (e.g., Ayala-Vazquez, Concepción-Guliam, Carvajal) — collectively reinforce the deference afforded to within- or downward-variant sentences.

3.2 The Court’s Legal Reasoning

1. Procedural-reasonableness step.
   • The sentencing judge expressly stated that he had considered the PSR, the parties’ memoranda, and all § 3553(a) factors.
   • Acknowledged Rosario’s youth, history of abuse, intellectual disability, and neuropsychological reports, but balanced these against (i) four homicide victims, (ii) the spree’s calculated nature, and (iii) Rosario’s continued violent threats in custody.
   • Imposed a downward variance from a Guideline life sentence to 480 months—demonstrating the mitigating factors were not ignored.
2. Disparity analysis.
   • § 3553(a)(6) requires courts to avoid unwarranted disparities; warranted disparities are permissible.
   • Different judges sentenced the co-defendants; some had not yet been sentenced when Rosario was. That alone complicates the comparison.
   • Rosario supplied no data on co-defendants’ criminal histories, roles, plea concessions, or Guideline calculations. Without that, the First Circuit refused to presume equivalence.
   • Citing Reyes-Santiago and Demers, the panel held that Rosario did not meet the evidentiary burden necessary to trigger serious disparity scrutiny.
3. Substantive-reasonableness step.
   • The sentence had a “plausible sentencing rationale and a defensible result” (Ayala-Vazquez). The district court balanced mitigation against the need for retribution, deterrence, and public safety.
   • The 40-year term, though harsh, was below the advisory life sentence and thus presumed reasonable.
   • Rosario’s argument that the court over-weighted aggravating factors amounted to a request for re-weighing, which an appellate court will not do absent manifest unreasonableness.

3.3 Likely Impact of the Decision

The decision does not blaze entirely new ground, but it sharpens existing First Circuit doctrine in three practical ways:

1. Clarifies the evidentiary burden on disparity claimants. A defendant must present concrete, record-based evidence showing that comparators are truly similar in Guideline range, criminal history, plea concessions, and role. Mere citation to lower sentences—even from the same indictment—is insufficient.
2. Signals deference where the district court grants any downward variance. Litigants appealing a sentence that is already below the Guideline range face an “especially steep uphill climb,” solidifying a practical presumption of reasonableness.
3. Cabins the relevance of Miller and juvenile-specific Eighth Amendment caselaw to non-mandatory LWOP situations, at least within the First Circuit’s sentencing-appeal framework.

Future defendants in the circuit—particularly youthful or intellectually-disabled offenders—will have to marshal far more robust comparator data when lodging § 3553(a)(6) challenges, and should not rely on Miller unless faced with de-facto or actual life-without-parole terms.

4. Complex Concepts Simplified

• Procedural vs. Substantive Reasonableness
  • Procedural questions ask whether the judge followed correct steps—calculating the Guidelines, considering § 3553(a) factors, avoiding clear errors of fact.
  • Substantive questions ask whether, given those steps, the final sentence is plainly too harsh or too lenient.
• § 3553(a) Factors
  The statute lists considerations such as the nature of the offense, defendant’s history, need for deterrence, protection of the public, and avoidance of unwarranted disparities.
• Downward Variance vs. Departure
  • A departure is a movement outside the Guideline range based on enumerated Guideline policy statements (e.g., § 5K2.13 diminished capacity).
  • A variance is any deviation based on the broader § 3553(a) factors once the court views the Guidelines as advisory.
• “Apples-to-Apples” Standard
  To show an unjustified disparity, the defendant must demonstrate that the proposed comparator has (i) similar criminal history; (ii) similar culpability/role; (iii) similar plea concessions; and (iv) was sentenced by the same law and Guidelines. Lacking any one of these, the disparity is typically “warranted.”
• Plain-Error Review
  Where an argument was not raised below, the appellate court will reverse only if there is (1) error, (2) that is plain/obvious, (3) affecting substantial rights, and (4) seriously impugning the fairness or integrity of the proceedings.

5. Conclusion

The First Circuit’s opinion in United States v. Rosario-Sánchez is a careful re-affirmation of sentencing-appeal fundamentals: defer to district-court discretion, demand rigorous proof for disparity arguments, and recognise the limited reach of juvenile-specific Eighth Amendment precedent absent a life-without-parole sentence. For practitioners, the case underscores the necessity of developing a factual record on comparators before the sentencing hearing, especially when different judges or different plea bargains are in play. For district judges, it validates the practice of acknowledging (§ 3553(a)) factors on the record—even briefly—and explaining why, notwithstanding mitigation, public safety and deterrence may require a lengthy term. As a precedential matter, the decision will likely be cited whenever co-defendant disparity claims are raised without sufficient “apples-to-apples” data.