United States v. Amos Koech, 992 F.3d 686

Amos Koech was convicted of commercial sex trafficking of a minor (18 U.S.C. § 1591(a)) and conspiracy (§ 1594(c)) for paying co‑defendant Andre Mathis $60 to have sex with 15‑year‑old C.D.; he was sentenced to 130 months.
Trial evidence: Mathis recruited and abused C.D., advertised her online, and “trained” her; C.D. visited Koech’s apartment multiple times, engaged in sexual acts, and was photographed nude.
Corroborating evidence included multiple text messages and phone calls between Koech and Mathis negotiating price, nude images recovered (and later deleted) from Koech’s Chinese‑made phone, and Koech’s statements/admissions to police.
The jury was instructed that § 1591(c)’s age mens rea could be satisfied if the defendant knew, recklessly disregarded, or had a “reasonable opportunity to observe” the victim’s age; the government argued alternate theories at closing.
The court also instructed the jury that conduct that “affects” interstate commerce need only do so to any degree (even minimal) and that use of phones/internet can be considered in determining the interstate nexus.
Koech appealed, arguing (1) § 1591(c)’s phrase “reasonable opportunity to observe” is unconstitutionally vague, (2) the interstate‑commerce jury instruction was erroneous because it allowed conviction based on potential rather than actual effects, and (3) the evidence was insufficient to show an interstate commerce nexus. The Eighth Circuit affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Vagueness of “reasonable opportunity to observe” in § 1591(c)	Statutory phrase is a familiar, ascertainable standard; as‑applied to the facts it gives fair notice and is constitutional	Phrase is void for vagueness and fails to give notice of prohibited conduct	Not unconstitutionally vague as applied; evidence showed Koech had a reasonable opportunity to observe C.D.
Jury instruction on interstate commerce (actual vs potential effect)	Instruction correctly required that conduct “affect” interstate commerce; need not prove defendant’s intent to affect commerce	Instruction wrongly permitted conviction based on merely potential effects (denying an actual‑effect defense)	Instruction acceptable; did not improperly eliminate actual‑effect requirement because it tied liability to natural consequences that affect commerce
Sufficiency of evidence of interstate commerce nexus	Texts/phone use (Chinese‑made phone), internet advertising, purchases across state lines, and conspiracy evidence established an interstate effect	The transaction was a local $60 exchange with no interstate travel or nexus	Evidence sufficient; reasonable jury could find the interstate‑commerce element beyond a reasonable doubt

United States v. Paul, 885 F.3d 1099 (8th Cir. 2018) (applied as‑applied vagueness principle to § 1591(c))
United States v. X‑Citement Video, Inc., 513 U.S. 64 (1994) (discussed age mens rea and personal confrontation of underage victims)
United States v. Cook, 782 F.3d 983 (8th Cir. 2015) (a defendant who engaged in clearly proscribed conduct cannot prevail on vagueness challenge as applied)
United States v. Mozie, 752 F.3d 1271 (11th Cir. 2014) ("reasonable opportunity to observe" and "reckless disregard" are familiar legal concepts)
Grayned v. City of Rockford, 408 U.S. 104 (1972) (vagueness doctrine; language rarely yields mathematical certainty)
United States v. Williams, 308 F.3d 833 (8th Cir. 2002) (error analysis for interstate‑commerce jury instructions)
United States v. Evans, 272 F.3d 1069 (8th Cir. 2001) (similar discussion of interstate‑commerce instruction errors)
Gonzales v. Raich, 545 U.S. 1 (2005) (commerce‑clause framework for regulating local economic activity as part of a class)
United States v. Lopez, 514 U.S. 549 (1995) (limits on Congress’s commerce power)
United States v. Corum, 362 F.3d 489 (8th Cir. 2004) (use of telephones can satisfy interstate‑commerce element)
United States v. Baston, 818 F.3d 651 (11th Cir. 2016) (phone and internet evidence supports interstate nexus in § 1591 prosecutions)
United States v. Collier, 932 F.3d 1067 (8th Cir. 2019) (standard for reviewing jury instructions)