United States v. Concepcion-Montijo, 875 F.3d 58

Defendant Herminio Concepción-Montijo pled guilty to being a felon in possession of a firearm (18 U.S.C. § 922(g)(1)).
District court sentenced him to the statutory maximum of 120 months, an upward variance from the Guidelines range recommended by probation.
Government sought a career-offender enhancement based in part on a prior Illinois residential burglary conviction, but relied on unauthenticated documents (probation letter, police report, docket printout) rather than paying for official Cook County records.
Concepción argued on appeal that the district court procedurally erred by relying on those unauthenticated documents to calculate the Guidelines sentencing range (GSR).
The district court explained its upward variance rested on Concepción's extensive, multi-jurisdictional history of drug and weapons offenses and stated it would have imposed the same 120-month sentence regardless of the specific GSR calculation.
On appeal the First Circuit considered both procedural (GSR calculation) and substantive (reasonableness of upward variance) challenges and affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Procedural error in GSR calculation	Gov: prior conviction supported enhancement despite informal proof	Concepción: court relied on unauthenticated documents so GSR was miscalculated	Affirmed — any GSR error was harmless because court would have imposed same sentence anyway
Substantive reasonableness of 120-month upward variance	Gov: variance justified by defendant's lengthy, serious criminal history and public safety concerns	Concepción: sentence was substantively unreasonable and undervalued his personal circumstances	Affirmed — court provided plausible rationale; variance not an abuse of discretion

United States v. Magee, 834 F.3d 30 (1st Cir.) (harmless error standard for Guidelines miscalculation)
United States v. Santiago-Rivera, 744 F.3d 229 (1st Cir.) (review of reasonableness of variances; need plausible rationale)
United States v. Martin, 520 F.3d 87 (1st Cir.) (sentencing rationale and defensible result as lynchpin of reasonableness)
United States v. Arroyo-Maldonado, 791 F.3d 193 (1st Cir.) (sentencing court may give greater weight to criminal history)
United States v. Flores-Machicote, 706 F.3d 16 (1st Cir.) (upward variance justified where Guidelines under-represent recidivism risk)
United States v. Politano, 522 F.3d 69 (1st Cir.) (upward variance justified when Guidelines underestimate likelihood of future crimes)