United States v. Francisca-Gamboa, 972 F.3d 1148

Background:

Rodriguez-Gamboa was removed after a California conviction for possession for sale of methamphetamine (Cal. Health & Safety Code § 11378) and later charged with illegal reentry under 8 U.S.C. § 1326.
California’s controlled-substances definitions expressly include both “optical and geometrical (diastereomeric) isomers” of listed drugs; the federal Controlled Substances Act (CSA) refers only to optical isomers of methamphetamine.
A prior Ninth Circuit decision (Lorenzo) had held California’s statute categorically overbroad because of the textual inclusion of geometric isomers, and the district court dismissed the § 1326 information on that basis.
The Ninth Court remanded for a limited evidentiary inquiry into the government’s contention that geometric isomers of methamphetamine do not chemically exist.
At a district-court hearing, unrebutted expert testimony established that methamphetamine’s molecular structure precludes geometric isomers; the district court so found.
The Ninth Circuit reviewed that factual finding for clear error and held that because geometric isomers are impossible, there is no realistic probability California would prosecute such conduct, so the state statute is a categorical match to the federal definition for this purpose.

Issues:

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the district court’s factual finding (geometric isomers don’t exist) is clearly erroneous	District court erred; statute’s parenthetical shows possible diastereomers; expert evidence insufficient	Unrebutted expert testimony shows methamphetamine cannot have geometric isomers	Finding not clearly erroneous; record overwhelmingly supports impossibility
Whether California’s textual inclusion of "geometrical" isomers makes the statute categorically overbroad despite impossibility of such isomers	Textual overbreadth controls; explicit broader wording ends categorical match	Duenas‑Alvarez requires a realistic probability of prosecuting nongeneric conduct; impossibility negates that probability	Impossibility means no realistic probability; statute is a categorical match to federal law
Whether ordering and relying on an evidentiary hearing conflicts with the categorical approach’s purpose	Categorical approach forbids fact-specific inquiries into convictions	Scientific inquiry into whether the overbroad conduct is possible is permissible and distinct from probing conviction facts	Evidentiary hearing was appropriate; scientific question does not undermine categorical approach
Whether this decision conflicts with Seventh Circuit precedent	Rodriguez implied other circuits treat textual overbreadth as dispositive	Government noted Seventh Circuit left scientific arguments open and did not decide the scientific question	No split: Seventh Circuit left door open; science-based proof can resolve overbreadth issue

Key Cases Cited

Gonzales v. Duenas‑Alvarez, 549 U.S. 183 (2007) (overbreadth requires a realistic probability, not a theoretical possibility, of prosecuting nongeneric conduct)
Taylor v. United States, 495 U.S. 575 (1990) (categorical approach compares statutory elements to generic federal offense)
Moncrieffe v. Holder, 569 U.S. 184 (2013) (reiterating Duenas‑Alvarez and requiring evidence of realistic probability of nongeneric prosecutions)
United States v. Grisel, 488 F.3d 844 (9th Cir. 2007) (textual overbreadth can establish realistic probability when nongeneric application is possible)
Quarles v. United States, 139 S. Ct. 1872 (2019) (state statute must substantially correspond to or be narrower than the federal generic offense)
United States v. Hinkson, 585 F.3d 1247 (9th Cir. 2009) (en banc) (clear‑error standard for review of district‑court factual findings)