United States v. Diggs: Distinct Overbreadth Theories Must Be Specifically Preserved; No Plain Error in Treating Florida “Stereoisomer” Cocaine Convictions as ACCA Predicates

Introduction

In this unpublished, consolidated Eleventh Circuit decision, the court affirms the Armed Career Criminal Act (ACCA) sentences imposed on Jimmy Derrick Diggs after his guilty pleas to two felon-in-possession counts under 18 U.S.C. § 922(g)(1). The appeal presents a familiar front in modern ACCA litigation: whether certain Florida cocaine convictions qualify as “serious drug offenses” under 18 U.S.C. § 924(e). The twist here lies in preservation and standard of review.

Before the district court, Diggs argued that Florida’s cocaine definition was categorically broader than federal law because the Florida schedule (at the relevant times) included ioflupane while the federal schedule did not. The district court rejected that argument as foreclosed by United States v. Jackson, 55 F.4th 846 (11th Cir. 2022), a holding later affirmed by the Supreme Court in Brown v. United States, 602 U.S. 101 (2024). On appeal, however, Diggs pivoted to a different mismatch theory: that Florida’s definition of cocaine included “any stereoisomer of cocaine,” while the federal definition listed only “optical and geometric isomers.” Because Diggs did not present that “isomer” argument below, the Eleventh Circuit reviewed only for plain error and affirmed.

This opinion does three important things. First, it underscores the Eleventh Circuit’s stringent preservation requirement: raising one overbreadth rationale (ioflupane) does not preserve a different one (isomers). Second, it reinforces that, under plain-error review, the absence of directly controlling precedent or clear statutory resolution defeats relief. Third, it harmonizes this case with the Circuit’s recent decision in United States v. Laines, 69 F.4th 1221 (11th Cir. 2023), which rejected a materially identical “stereoisomer” ACCA challenge under plain-error review.

Summary of the Opinion

The Eleventh Circuit affirmed Diggs’s sentences as an armed career criminal under § 924(e). The panel held:

Preservation: Diggs did not preserve his “stereoisomer” mismatch theory because, in the district court, he argued only about ioflupane. Those arguments are “substantively different” and require different legal and factual showings.
Plain Error: Reviewing the new isomer argument for plain error, the court found no “plain” error. There is no Supreme Court or Eleventh Circuit precedent clearly holding that Florida’s inclusion of “any stereoisomer of cocaine” is broader than the federal schedule’s reference to “optical and geometric isomers,” and Laines specifically rejected a similar claim on plain-error review. Under Eleventh Circuit plain-error doctrine, the lack of controlling precedent or explicit statutory language resolving the point defeats relief.
Result: The district court did not plainly err in counting Diggs’s Florida cocaine convictions as “serious drug offenses,” so the ACCA sentences stand.

Analysis

Precedents Cited and Their Influence

Brown v. United States, 602 U.S. 101 (2024): The Supreme Court held that whether a prior state drug conviction qualifies as an ACCA predicate turns on whether the state and federal schedules matched when the state offense was committed. The panel quotes Brown’s formulation: a prior state drug conviction counts if state and federal schedules “matched when the state drug offense was committed” (id. at 119). Although Brown addressed the temporal comparison rule (not isomer taxonomy), it affirmed the Eleventh Circuit’s approach in Jackson and foreclosed the district court’s earlier ioflupane objection.
United States v. Jackson, 55 F.4th 846 (11th Cir. 2022), aff’d sub nom. Brown: Jackson provided the Eleventh Circuit framework for ACCA schedule matching later endorsed in Brown. In Diggs, the district court rejected the ioflupane-based overbreadth objection as foreclosed by Jackson, a step the Eleventh Circuit acknowledges in recounting the procedural posture.
United States v. Laines, 69 F.4th 1221 (11th Cir. 2023): Laines is the centerpiece for the isomer issue. It held that a district court did not plainly err by treating a Florida cocaine conviction as an ACCA predicate even though Florida’s definition included “any stereoisomer of cocaine” while the federal definition covered only “optical and geometric isomers.” Because the defendant there, like Diggs, could not point to binding authority establishing that Florida’s definition was clearly overbroad, the claim failed under plain error. The Diggs panel applies Laines directly to dispose of the same isomer-based mismatch.
United States v. Straub, 508 F.3d 1003 (11th Cir. 2007); United States v. Zinn, 321 F.3d 1084 (11th Cir. 2003); United States v. Corbett, 921 F.3d 1032 (11th Cir. 2019): These cases articulate the preservation rule: to preserve an appellate claim, the objector must “apprise” the district court and the government of the specific grounds for relief, with sufficiently “specific factual and legal argumentation.” The court relies on these authorities to conclude that Diggs’s ioflupane theory did not fairly present the distinct isomer theory.
United States v. Ramirez-Flores, 743 F.3d 816 (11th Cir. 2014): Ramirez-Flores holds that arguments are unpreserved if they are “substantively different” from those made below. The panel analogizes: just as a generic/non-generic burglary argument differed from a “non-violent burglary” description argument, an ioflupane inclusion argument differs from an isomer-taxonomy argument.
United States v. Lejarde-Rada, 319 F.3d 1288 (11th Cir. 2003): A cornerstone of Eleventh Circuit plain-error jurisprudence: absent explicit statutory text resolving the issue or directly controlling precedent from the Supreme Court or the Eleventh Circuit, an error is not “plain.” The Diggs panel invokes Lejarde-Rada to emphasize why the isomer claim cannot clear the plain-error threshold.

Legal Reasoning

The court’s reasoning proceeds in two steps.

Preservation: The Eleventh Circuit first holds that Diggs did not preserve the isomer mismatch argument. While both the ioflupane and isomer theories are “overbreadth” theories, they are analytically distinct. The isomer argument requires different legal contentions (textual parsing of “stereoisomer” vs. “optical and geometric isomers”), potentially different scientific evidence (which isomers of cocaine exist and which the statutes capture), and different rebuttals. Because Diggs never mentioned isomers below, neither the government nor the district court was fairly alerted. Under Straub, Zinn, Corbett, and Ramirez-Flores, that is insufficient to preserve the claim.
Plain Error (Unpreserved Isomer Theory): Applying plain-error review, the panel concludes there was no “plain” error in treating Diggs’s Florida cocaine convictions as ACCA predicates. The court reasons:
- The “plainness” inquiry turns on “current law.” Where there is no controlling Supreme Court or Eleventh Circuit decision squarely holding that Florida’s inclusion of “any stereoisomer of cocaine” renders its schedule broader than the federal schedule’s “optical and geometric isomers,” there can be no plain error under Lejarde-Rada.
- Laines is dispositive for this standard of review. It rejected the same mismatch claim on plain-error grounds because no binding authority clearly established overbreadth. Diggs’s claim is thus foreclosed by Laines’s logic.
Because the claim fails at the “plainness” step (and the panel does not find an error that is “obvious or clear under current law”), it does not need to reach substantial-rights or fairness considerations.

Impact

Although unpublished, this decision is an important signal in three respects:

Preservation-by-specificity is critical in ACCA schedule-mismatch litigation: Defendants challenging Florida cocaine predicates must present every distinct overbreadth theory in the district court—ioflupane issues, isomer-taxonomy issues, or any other textual mismatch—with specificity. Raising one does not preserve the other. This decision provides a clear roadmap for how the Eleventh Circuit will parse “substantively different” grounds at sentencing.
Isomer-based mismatch claims continue to face a high bar under plain error: Laines remains the controlling signpost for unpreserved “stereoisomer” arguments. Unless and until the Supreme Court or the Eleventh Circuit (in a published, precedential opinion) squarely holds that Florida’s inclusion of “any stereoisomer” renders its cocaine schedule broader than the federal definition, defendants will not succeed on plain error.
Brown’s temporal matching rule is stable: The court’s reliance on Brown (and Jackson) confirms that the time-of-offense schedules govern ACCA matching. Counsel must identify the exact versions of Florida’s and the federal schedules in effect when the predicate state offenses occurred and build any overbreadth theory anchored in those texts.

Practical implications for litigants:

Defense counsel: To preserve isomer-based arguments, explicitly argue that “stereoisomer” in Fla. Stat. § 893.03(2)(a)(4) sweeps in forms of cocaine not encompassed by “optical and geometric isomers” in 21 U.S.C. § 812 Schedule II at the relevant time. Consider supporting the argument with authoritative definitions, expert testimony, or scientific sources explaining the stereochemistry of cocaine and whether any non-optical, non-geometric stereoisomers exist that would render Florida’s coverage broader. Request a specific ruling.
Prosecutors: Emphasize the absence of binding precedent establishing overbreadth, invoke Laines for plain-error cases, and argue that any asserted textual differences do not translate into categorical overbreadth unless the defendant shows that the state provision necessarily covers substances not federally controlled at the relevant time.
District courts: When presented with isomer arguments, seek targeted briefing on statutory text and scientific underpinnings. Explicit findings can clarify the record for any appellate review beyond plain error.

Complex Concepts Simplified

ACCA (Armed Career Criminal Act): A federal law, 18 U.S.C. § 924(e), imposing a 15-year mandatory minimum on felon-in-possession defendants who have three prior convictions for “violent felonies” or “serious drug offenses,” committed on different occasions.
Serious Drug Offense: Under § 924(e)(2)(A), a state offense involving manufacturing, distributing, or possessing with intent to distribute a controlled substance, punishable by 10 or more years. Whether a state drug conviction qualifies often turns on whether the state’s definition of the substance matches the federal Controlled Substances Act (CSA) at the relevant time.
Categorical Approach: Courts compare the statutory elements (or, in drug cases, the controlled substance definitions) of the prior offense to the federal definition without considering the defendant’s actual conduct. If the state law’s coverage is the same as or narrower than federal law, the conviction qualifies; if the state law is broader (i.e., it criminalizes substances not federally controlled), it does not.
Schedule Mismatch and Brown’s Timing Rule: Brown v. United States instructs that courts compare the state and federal schedules as they existed when the state offense occurred.
Ioflupane: A cocaine derivative used in certain medical imaging. Its inclusion or exclusion from drug schedules has fueled “overbreadth” arguments that Florida controlled ioflupane when federal law did not (or vice versa). Jackson and Brown foreclose certain ioflupane-based challenges in the Eleventh Circuit.
Isomers (Optical, Geometric, Stereoisomers):
- Stereoisomers are molecules with the same formula and atom connectivity but different three-dimensional arrangements. This is the umbrella category.
- Optical isomers (enantiomers) are mirror-image stereoisomers that rotate plane-polarized light differently.
- Geometric isomers (cis/trans or E/Z) are a type of diastereomer arising from restricted rotation, typically around double bonds or ring structures.
Florida’s “any stereoisomer” language is, textually, broader than “optical and geometric isomers.” Whether that textual breadth translates into categorical overbreadth depends on legal interpretation and, sometimes, scientific facts about the substance’s possible isomers. Under Eleventh Circuit plain-error doctrine, absent clear controlling precedent or statutory text, courts will not find “plain” error.
Preservation of Error: To preserve an issue for appeal, the party must clearly articulate the specific legal and factual basis in the district court so the court and the opposing party can address it. Raising a general category (e.g., “overbreadth”) does not preserve every distinct sub-theory (e.g., ioflupane vs. isomer taxonomy).
Plain-Error Review: For unpreserved claims, the appellant must show (1) an error, (2) that is “plain” (obvious under current law), (3) affecting substantial rights, and (4) seriously affecting the fairness, integrity, or public reputation of judicial proceedings. An error is not “plain” where no binding precedent or unmistakable statutory text resolves the issue.

Conclusion

United States v. Diggs reinforces two practical and doctrinal points in ACCA predicate litigation. First, preservation is specific: a defendant who challenges Florida drug predicates must distinctly raise each textual overbreadth theory—ioflupane, isomer taxonomy, or otherwise—at sentencing to obtain plenary appellate review. Second, on plain-error review, the Eleventh Circuit will not invalidate ACCA predicates based on the Florida “stereoisomer” argument absent clear, on-point authority or explicit statutory language demonstrating overbreadth. In aligning with Laines and framed by Brown’s temporal matching rule, this decision signals that isomer-based challenges to Florida cocaine predicates will continue to falter on plain-error review, and that defense counsel must carefully curate and preserve these arguments in the district court to keep them alive on appeal.

Bottom line: The Eleventh Circuit affirms Diggs’s ACCA sentences because (1) the isomer theory was not preserved, and (2) even if considered, any error was not “plain” under current law. The opinion underscores a broader lesson—distinct overbreadth theories are not interchangeable, and success in this niche of ACCA jurisprudence hinges on meticulous issue preservation and targeted, authoritative support.