UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT UNITED STATES OF AMERICA, No. 23-1703 D.C. No. Plaintiff - Appellant, 3:22-cr-00068- v. ART-CLB-1 TRISTON HARRIS STEINMAN, OPINION Defendant - Appellee.

Appeal from the United States District Court for the District of Nevada Anne R. Traum, District Judge, Presiding

Argued and Submitted December 5, 2024 San Francisco, California

Filed March 5, 2025

Before: MILAN D. SMITH, JR. and PATRICK J. BUMATAY, Circuit Judges, and GEORGE H. WU, Senior District Judge. *

Opinion by Judge Milan D. Smith, Jr.; Concurrence by Judge George H. Wu * The Honorable George H. Wu, United States Senior District Judge for the Central District of California, sitting by designation. 2 USA V. STEINMAN

SUMMARY **

Criminal Law

The panel reversed the district court’s order suppressing evidence seized from Triston Harris Steinman’s car following a traffic stop in a case in which Steinman is charged with being a felon in possession of ammunition and possession of unregistered firearms. The panel held that the district court erred in concluding that Nevada State Trooper William Boyer violated Steinman’s constitutional rights by unlawfully prolonging the traffic stop. Trooper Boyer had reasonable suspicion of an independent offense after he learned of Steinman’s felony conviction, and he did not measurably prolong the traffic stop up to that point. The panel held that the district court erred in concluding that Trooper Boyer lacked probable cause to seize Steinman’s automobile. To the contrary, Trooper Boyer had probable cause to believe that the automobile contained evidence of two independent offenses—possession of ammunition in violation of federal law and possession of firearms in violation of Nevada law. As to the issue of the “cross-enforcement” of the Fourth Amendment—whether an officer employed by one government can justify a search or seizure based on a violation of a different government’s law—the panel concluded that the fact that possession of

** This summary constitutes no part of the opinion of the court. It has been prepared by court staff for the convenience of the reader. USA V. STEINMAN 3

ammunition by a felon is illegal only under federal law poses no barrier to Trooper Boyer’s seizure of the car. The panel held that the district court erred in concluding that warrant overbreadth requires suppression. The panel did not disturb the district court’s ruling that the search warrant was unconstitutionally overbroad, but it was nonetheless error for the district court to exclude the fruits of the search because the search of Steinman’s vehicle would have been permissible under the automobile exception to the Fourth Amendment’s warrant requirement. District Judge Wu concurred with the majority opinion except for Part II.B.1. He wrote that the panel need not— and should not—break new ground by addressing the undeveloped and potentially sweeping “cross-enforcement” issue.

COUNSEL Peter H. Walkingshaw (argued), Assistant United States Attorney; Office of the United States Attorney, United States Department of Justice, Reno, Nevada; Adam M. Flake and Robert L. Ellman, Appellate Chiefs; Jason M. Frierson, United States Attorney; Office of the United States Attorney, United States Department of Justice, Las Vegas, Nevada; for Plaintiff-Appellant. Jeremy C. Baron (argued), Assistant Federal Public Defender; Rene L. Valladares, Federal