Preservation Matters in ACCA: ioflupane overbreadth does not preserve isomer arguments; no plain error in treating Florida “stereoisomer” cocaine convictions as ACCA predicates

Commentary on United States v. Jimmy Diggs, No. 24-10232 & No. 24-10233 (11th Cir. Nov. 6, 2025) (per curiam) (unpublished)

Introduction

This consolidated, unpublished Eleventh Circuit decision affirms the Armed Career Criminal Act (ACCA) sentences imposed on Jimmy Derrick Diggs following his guilty pleas to two felon-in-possession counts under 18 U.S.C. § 922(g)(1). The dispositive question was whether two prior Florida cocaine convictions qualify as “serious drug offenses” for ACCA purposes. At sentencing, Diggs argued Florida’s cocaine schedules were categorically broader than federal schedules because Florida included ioflupane while the federal schedules did not. After the Supreme Court’s decision in Brown v. United States, which affirmed Eleventh Circuit precedent on the schedules-match rule, that argument failed.

On appeal, Diggs pivoted: he contended for the first time that Florida’s statutory reference to “any stereoisomer of cocaine” is broader than the federal schedules’ reference to “optical and geometric isomers,” so his Florida cocaine convictions should not qualify as ACCA predicates. Because Diggs did not present that isomer-based theory below, the panel reviewed for plain error and, relying on United States v. Laines, held there was no plain error in treating the Florida convictions as serious drug offenses. The court also held that raising an ioflupane-based overbreadth theory at sentencing did not preserve an isomer-based overbreadth theory, as the two objections are “substantively different.”

The opinion thus reinforces two interlocking principles: (1) issue preservation in federal sentencing demands specificity—distinct statutory-overbreadth theories must be distinctly raised, and (2) under plain-error review, the absence of binding precedent establishing overbreadth defeats relief, particularly where Eleventh Circuit authority (Laines) points in the opposite direction.

Summary of the Opinion

The Eleventh Circuit affirmed Diggs’s ACCA sentences stemming from two § 922(g)(1) convictions.
Diggs’s new appellate theory—that Florida’s inclusion of “any stereoisomer of cocaine” is broader than the federal schedules’ “optical and geometric isomers”—was not preserved because he only argued an ioflupane mismatch in the district court.
Applying plain-error review, the panel found no plain error. Citing United States v. Laines, it concluded there is no binding authority establishing that Florida’s cocaine definition is clearly overbroad on the isomer question, and Laines suggests the contrary.
The panel reiterated Brown v. United States’s schedules-match rule: a prior state drug conviction qualifies as an ACCA predicate if the state and federal schedules matched when the state offense was committed.

Analysis

Precedents Cited and How They Shaped the Decision

Brown v. United States, 602 U.S. 101 (2024). The Supreme Court affirmed the Eleventh Circuit’s approach from United States v. Jackson, holding that for ACCA “serious drug offense” analysis, courts ask whether the state and federal schedules matched at the time the defendant committed the state drug offense. The Diggs panel quoted Brown’s formulation: a state drug conviction is a predicate “if the drugs on the federal and state schedules matched when the state drug offense was committed.” This neutralized Diggs’s original ioflupane-based objection to the ACCA designation at sentencing.
United States v. Jackson, 55 F.4th 846 (11th Cir. 2022), aff’d sub nom. Brown v. United States. Jackson established within the circuit the time-of-offense schedules-match rule later affirmed in Brown. The district court relied on Jackson to overrule Diggs’s ioflupane argument; the panel noted Jackson “had nothing to do with isomers,” reinforcing that Diggs’s new appellate theory was distinct and unpreserved.
United States v. Laines, 69 F.4th 1221 (11th Cir. 2023). Laines is the key authority for the isomer issue under plain-error review. There, the Eleventh Circuit rejected a similar claim that Florida’s reference to “any stereoisomer of cocaine” rendered it broader than the federal schedules’ “optical and geometric isomers.” The court held there was no plain error because the defendant identified no binding authority showing overbreadth; if anything, circuit law suggested the opposite. Diggs’s panel applied the same logic and outcome.
Issue-preservation authorities:
- United States v. Straub, 508 F.3d 1003 (11th Cir. 2007): An objection must sufficiently apprise the court and opposing party of the specific grounds for later appellate relief.
- United States v. Zinn, 321 F.3d 1084 (11th Cir. 2003): The burden rests on the defendant to articulate the specific nature of the objection so the district court has a fair opportunity to consider it.
- United States v. Corbett, 921 F.3d 1032 (11th Cir. 2019): Specific factual and legal argumentation must be presented at every stage of sentencing to preserve an issue.
- United States v. Ramirez-Flores, 743 F.3d 816 (11th Cir. 2014): An argument raised on appeal that is “substantively different” from the objection below is unpreserved.
These cases drove the panel’s threshold conclusion that an ioflupane mismatch argument does not preserve a distinct isomer mismatch argument.
United States v. Lejarde-Rada, 319 F.3d 1288 (11th Cir. 2003). Under plain-error review, if neither statutory text nor binding precedent clearly resolves the issue, there is no “plain” error. The panel invoked this principle to deny relief on Diggs’s new isomer claim.

Legal Reasoning

Framing the ACCA inquiry. ACCA imposes a 15-year minimum for a § 922(g) offender with three qualifying predicates—violent felonies or serious drug offenses—committed on different occasions. A state drug conviction qualifies only if, under the categorical approach, the state definition does not cover substances beyond those controlled under federal law. After Brown, the relevant comparison is whether the state and federal schedules “matched when the state drug offense was committed.”
Preservation: distinct overbreadth theories must be distinctly asserted. Diggs’s sentencing objection argued Florida was overbroad because it included ioflupane. On appeal he argued Florida was overbroad because it included “any stereoisomer” of cocaine, while the federal schedules list “optical and geometric isomers.” The panel held these are “substantively different” objections: they involve different textual comparisons, different chemistry issues, and potentially different evidentiary showings. Because Diggs never raised isomers below, the district court had no opportunity to consider that theory, and the government had no opportunity to respond. Thus, the isomer theory was unpreserved.
Plain-error standard controls. With the issue unpreserved, Diggs had to show (i) error, (ii) that is clear or obvious (plain) under current law, and (iii) that affected substantial rights. The court resolved the second step: there was no “plain” error because there is no Supreme Court or Eleventh Circuit precedent holding Florida’s reference to “any stereoisomer of cocaine” renders the statute categorically broader than the federal schedules. Indeed, Laines indicates the opposite on plain-error review.
Categorical approach and schedules-match applied. The panel reiterated the governing rule: “all the controlled substances covered by the state law must also be controlled substances under federal law.” On the isomer question, no binding authority establishes that Florida criminalizes a class of cocaine-related stereoisomers that were not federally controlled at the time of the state offenses. Absent such authority, the district court’s use of Diggs’s Florida cocaine convictions as ACCA predicates cannot be plainly erroneous.
Disposition. Because the isomer theory was unpreserved and, in any event, not clearly supported by binding precedent, the court affirmed the ACCA-enhanced sentences.

Impact

Although unpublished, this opinion provides a clear roadmap for ACCA litigation in the Eleventh Circuit in the wake of Brown:

Preservation discipline at sentencing is critical. Defense counsel must distinctly articulate each alleged overbreadth theory—ioflupane, isomers, or others—at sentencing. A general “overbreadth” objection is not enough; different chemical or textual theories are treated as different objections. Failure to specify will confine appellate review to the demanding plain-error standard.
Isomer-based Florida cocaine challenges are uphill on plain-error review. Laines already signaled that, absent binding authority showing Florida’s “any stereoisomer” language sweeps more broadly than the federal “optical and geometric isomers” phrase, there is no plain error. Diggs reaffirms that posture. To prevail in a future case, a defendant would likely need to (a) preserve the isomer theory, (b) develop the statutory and scientific record, and (c) identify controlling authority or persuasive analysis demonstrating actual overbreadth at the time of the state offenses.
Brown and Jackson largely resolve ioflupane-based challenges. The schedules-match rule looks to the time of the state offense, undermining many ioflupane mismatch theories premised on later federal descheduling. District courts in the Eleventh Circuit will continue to treat such challenges as foreclosed by Jackson and Brown.
Practical effect on Florida drug predicates. In the near term, Florida cocaine convictions will continue to qualify as ACCA predicates in the Eleventh Circuit, especially where the only mismatch claim is the isomer phrasing and the issue was not specifically preserved below.
Guidance for record-building. If defendants wish to press the isomer mismatch theory, they should: (1) raise it explicitly at sentencing, (2) present statutory and scientific support explaining why “stereoisomer” materially exceeds “optical and geometric isomers” as used in the federal schedules at the relevant time, and (3) be prepared to distinguish Laines or identify superseding authority.

Complex Concepts Simplified

ACCA “serious drug offense.” Under 18 U.S.C. § 924(e)(1), a defendant convicted under § 922(g) faces a 15-year minimum if he has three prior qualifying convictions. A state drug conviction qualifies if it involves manufacturing, distributing, or possessing with intent to distribute a federally controlled substance and carries a sufficient maximum term. Courts compare the state schedule to the federal schedule to ensure the state law does not cover substances the federal law does not.
Categorical approach. Courts look at the statutory definitions—not the facts of the defendant’s conduct—to see whether the state offense’s scope matches or is narrower than the federal definition.
Schedules-match timing (Brown/Jackson rule). The comparison is made as of when the state drug offense occurred, not when the federal firearm offense occurred or when the federal sentencing takes place.
Isomers and stereochemistry (why it matters).
- Stereoisomers are molecules with the same atoms connected in the same order but arranged differently in three-dimensional space.
- Optical isomers (enantiomers) are mirror-image pairs; geometric isomers (a subset of diastereomers) differ based on spatial arrangement around a double bond or ring (e.g., cis/trans).
- Florida’s “any stereoisomer of cocaine” could be read to encompass more categories than just “optical and geometric isomers.” The federal schedules specifically list “optical and geometric isomers.” If Florida’s definition truly captured additional stereoisomers not covered federally at the relevant time, the state statute would be broader and the conviction might not qualify under ACCA. But the Eleventh Circuit has not recognized such overbreadth in binding precedent; hence no plain error.
Plain error review. When a defendant fails to preserve an objection, he must show a clear or obvious error under current law that affected his substantial rights. If there is no Supreme Court or Eleventh Circuit decision squarely establishing the error, the court will not find it “plain.”
Issue preservation. To preserve an issue, a defendant must clearly present the specific legal and factual grounds to the district court, so that court and the government have a fair chance to consider and respond. Raising one overbreadth theory (e.g., ioflupane) does not preserve a different one (e.g., isomers).

Conclusion

United States v. Diggs underscores the Eleventh Circuit’s disciplined approach to ACCA predicate analysis after Brown. The panel held that a defendant who raised only an ioflupane-based mismatch below did not preserve a distinct isomer-based mismatch theory for appeal. On plain-error review, and guided by Laines, the court declined to find Florida’s “any stereoisomer of cocaine” language categorically broader than the federal schedules’ “optical and geometric isomers.”

The key takeaways are straightforward:

Distinct statutory-overbreadth arguments must be distinctly preserved at sentencing.
Absent binding precedent clearly establishing overbreadth, isomer-based challenges to Florida cocaine predicates will not succeed on plain-error review.
Brown’s time-of-offense schedules-match rule continues to cabin ioflupane-based challenges in ACCA cases.

While unpublished, Diggs offers a practical signal to litigants: in ACCA cases involving Florida drug predicates, preservation and precise framing of overbreadth theories at sentencing are decisive, and the Eleventh Circuit’s current trajectory disfavors isomer-based mismatch claims absent a developed record and controlling authority.