United States v. John Yang, 39 F.4th 893

At ~1:30 a.m. in a Green Bay residential block known for drug activity (826 Kellogg St.), officers had received prior intelligence about suspected narcotics trafficking.
Officer Harvath observed a Dodge Ram parked with engine running and headlights off; he saw John Yang walking from the vicinity of 826 Kellogg toward the truck.
Harvath followed; during pursuit he believed the truck rolled through a stop sign. Officer Russell separately reported an earlier encounter with Yang and the same truck at a gas station where Yang had acted "shady."
Officers stopped the truck, questioned occupants, called for a canine unit, and processed IDs; the encounter lasted under six minutes before an altercation.
When officers ordered occupants out, Yang reached for his waist, a struggle ensued, and a handgun plus packages of methamphetamine and marijuana fell out; more meth was later found in the truck.
Yang moved to suppress the physical evidence; the district court credited officers’ testimony, denied suppression (finding reasonable suspicion for the stop and no unlawful prolongation), and Yang appealed after pleading guilty conditionally.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the traffic stop was supported by reasonable suspicion	Yang: dashcam and facts do not show a traffic violation or sufficient suspicion of drug activity	Govt: Harvath reasonably believed truck rolled through stop sign and had specific, articulable facts (time, location, engine on/lights off, Yang walking from suspected drug house) supporting drug-suspicion	Stop upheld: district court credibility findings not clearly erroneous; totality of circumstances gave reasonable suspicion for traffic violation and drug investigation
Whether officers unlawfully prolonged the stop	Yang: questioning about travel plans, ownership, weapons, and past conduct at the gas station exceeded scope and extended seizure	Govt: issue waived below; questions were within mission to investigate drugs and routine inquiries tied to traffic-stop mission (travel, registration, officer safety)	Challenge waived/forfeited; in any event questions were permissible and did not unlawfully extend the stop

Terry v. Ohio, 392 U.S. 1 (Terry standard: specific, articulable facts for investigatory stop)
United States v. Arvizu, 534 U.S. 266 (totality of the circumstances analysis for reasonable suspicion)
Rodriguez v. United States, 575 U.S. 348 (scope/duration of traffic stop tied to mission of stop)
Navarette v. California, 572 U.S. 393 (reasonable suspicion need not rule out innocent conduct)
Arizona v. Johnson, 555 U.S. 323 (officer questions unrelated to stop permitted if they do not measurably extend seizure)
District of Columbia v. Wesby, 138 S. Ct. 577 (do not engage in divide-and-conquer; consider combined inferences)
United States v. Cole, 21 F.4th 421 (7th Cir.: duration determined by stop’s mission; travel-plan and routine ID inquiries permissible)
United States v. Rodriguez-Escalera, 884 F.3d 661 (articulable facts and reasonable inferences for Terry analysis)