United States v. Leffler, 942 F.3d 1192

Police stopped a reported-stolen Ford Escape at ~midnight; occupants detained after officers observed persons moving between the Escape and a disabled truck.
A loaded pistol was found on the ground; Defendant Leffler told officers the pistol and items in the Escape belonged to him.
In the Escape’s cargo area officers found a duffel bag with magazines, ammunition, two disabled grenades, five long guns (including a Mossberg modified into a short‑barreled shotgun), ~42 grams of methamphetamine, scales, and small baggies.
A jury convicted Leffler of multiple counts, including possession of a short‑barreled shotgun in furtherance of a drug‑trafficking crime (18 U.S.C. § 924(c)(1)(B)(i)).
At trial Leffler moved for judgment of acquittal arguing certain firearms were not shown operable; the motion did not advance the nexus/in‑furtherance argument he now urges on appeal. The district court denied the motion and sentenced Leffler to 171 months.
On appeal Leffler argues the Government failed to prove the required nexus between the short‑barreled shotgun and drug trafficking; the Tenth Circuit held he waived that argument by failing to preserve it and by not arguing plain error in his opening brief, and affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the evidence was sufficient to show Leffler possessed the short‑barreled shotgun "in furtherance" of drug trafficking under § 924(c)(1)(B)(i)	Government (appellee): Leffler failed to preserve the nexus argument below and failed to argue plain error in his opening brief—thus the claim is waived; if considered, the evidence supports conviction	Leffler: The Government presented insufficient evidence of the requisite nexus between the shotgun and drug trafficking	Court: Leffler waived the claim (failed to preserve and did not properly raise plain‑error in opening brief); declined to reach the merits and affirmed conviction

United States v. Serrato, 742 F.3d 461 (10th Cir. 2014) (standard for reviewing sufficiency of the evidence)
Singleton v. Wulff, 428 U.S. 106 (1976) (appellate courts generally do not consider issues not passed upon below)
Richison v. Ernest Group, Inc., 634 F.3d 1123 (10th Cir. 2011) (distinguishing forfeiture and waiver; consequences for appellate review)
United States v. Goode, 483 F.3d 676 (10th Cir. 2007) (defendant must raise insufficiency claims in district court via Rule 29 motion)
United States v. Olano, 507 U.S. 725 (1993) (plain‑error review framework)
United States v. Zander, 794 F.3d 1220 (10th Cir. 2015) (discretion to consider plain error raised in reply in limited circumstances)
United States v. Courtney, 816 F.3d 681 (10th Cir. 2016) (addressing when courts may exercise discretion to review plain error raised first in reply brief)
United States v. Lamirand, 669 F.3d 1091 (10th Cir. 2012) (failure to argue for plain error on appeal ordinarily results in waiver)