United States v. Arvizu, 534 U.S. 266 (2002), is a case in which the Supreme Court of the United States unanimously reaffirmed the proposition that the Fourth Amendment required courts to analyze the reasonableness of a traffic stop based on the totality of the circumstances instead of examining the plausibility of each reason an officer gives for stopping a motorist individually.

U.S. Border Patrol agent Clinton Stoddard was working a checkpoint on U.S. Highway 191 north of Douglas, Arizona on an afternoon in January 1998.

As Stoddard was driving alongside the car, the driver abruptly signaled a turn onto the last available road that would avoid the checkpoint.

Stoddard radioed for a registration check on the minivan, and found out that it was registered to an address in Douglas known for heavy narcotics trafficking.

In federal court, he asked to suppress the marijuana, arguing that Stoddard did not have reasonable suspicion to stop him.

According to the Court, the approach taken by the Ninth Circuit, in which it found that seven of Stoddard's ten reasons were susceptible of an innocent explanation, did not examine the totality of the circumstances and thus ran counter to the de novo review that the Court had previously ruled should apply to appellate review of reasonable suspicion determinations.

Even so, he criticized the Court's deference to a district judge's "factual inferences," finding it to be incompatible with de novo review.