Navarette v. California, 572 U.S. 393 (2014), was a case in which the United States Supreme Court clarified when police officers may make arrests or conduct temporary detentions based on information provided by anonymous tips.

At trial, the occupants of the car argued that the traffic stop violated the Fourth Amendment of the United States Constitution, because the tip was unreliable, and officers did not personally observe criminal activity.

[6] Officers may not rely upon a mere "hunch", but the level of suspicion required to conduct a traffic stop is “considerably less than proof of wrongdoing by a preponderance of the evidence”, and less than is necessary for probable cause.

[13] The Court explained that if "an informant is shown to be right about some things, he is probably right about other facts that he has alleged, including the claim that the object of the tip is engaged in criminal activity.

[17] The Supreme Court of California would later rely upon this "bomb exception" in People v. Wells, when it ruled that an anonymous tip that accurately described a vehicle “weaving all over the roadway” justified a traffic stop.

[23] CHP dispatchers relayed the report to officers in the geographic area, and the vehicle was soon spotted traveling southbound at mile marker 66 near Fort Bragg, California.

[27] On August 26, 2008, a felony complaint was filed in Mendocino County Superior Court, charging Lorenzo Prado Navarette and Jose Prado Navarette with transportation of marijuana in violation of section 11360(a) of the California Health and Safety Code, and possession of marijuana for sale in violation of section 11359 of the California Health and Safety Code.

[32] Relying on the "public safety" exception established in People v. Wells, the court held that "ongoing danger to other motorists [justified] the stop without direct corroboration of the vehicle's illegal activity".

[37][fn 3] Writing for a majority of the Court, Justice Clarence Thomas held that the 911 call contained sufficient indicia of reliability to justify the traffic stop.

[41] Justice Thomas began his opinion by emphasizing that the Supreme Court had "firmly rejected the argument that reasonable cause for an investigative stop can only be based on the officer’s personal observation, rather than on information supplied by another person.”[42] By identifying the make, model, and license plate number of the pickup truck, Justice Thomas argued that "the caller necessarily claimed eyewitness knowledge of the alleged dangerous driving," and that basis of knowledge supported the tip's reliability.

[45] Justice Thomas also clarified that officers need not "rule out the possibility of innocent conduct" before making a traffic stop based on an anonymous tip.

[54] Justice Scalia also criticized the majority's conclusion that the tip provided reasonable suspicion that Lorenzo and Jose Prado Navarette were driving while drunk, because "the truck might have swerved to avoid an animal, a pothole, or a jaywalking pedestrian .... Or, indeed, he might have intentionally forced the tipster off the road because of some personal animus, or hostility to her 'Make Love, Not War' bumper sticker.

"[55] Furthermore, Justice Scalia argued that one discrete instance of irregular driving does not give rise to the reasonable suspicion of an ongoing threat of an intoxicated driver on the road.

[56] Justice Scalia also argued that the anonymous tip's claims of reckless driving were ultimately discredited by the fact that officers followed Lorenzo and Jose for five minutes, but observed nothing suspicious.

"[68] Scholars have observed that Navarette marked a departure from earlier precedent on the subject of anonymous tips, and some have argued that the case signifies a "dilution" of the Fourth Amendment's reasonable suspicion standard.

[69] One analyst argued that this departure "could encourage passive and sloppy policing, for officers will be tempted to rely on easily acquired anonymous tips rather than engage in arduous collection of evidence.