This short paper focuses on whether the Fourth Amendment permits police, during a routine traffic stop, to arbitrarily question motorists about subjects unrelated to the purpose of the traffic stop. The paper was prompted by a recent Ninth Circuit ruling, United States v. Mendez, 476 F.3d 1077 (9th Cir. 2007), which was authored by Judge Stephen Reinhardt. Prior to Mendez, the Ninth Circuit had taken the position that the Fourth Amendment barred police from questioning motorists about subjects unrelated to the purpose of a traffic stop, unless there was independent suspicion for such questioning. This rule was based on the principle that the Fourth Amendment limits the scope of a traffic stop in the same way that the amendment, as announced in Terry v. Ohio, restricts police activity during an investigative detention to actions reasonably related to the justification for the detention. In Mendez, however, Judge Reinhardt reversed circuit precedent and ruled that during routine traffic stops, police are free to questions motorists about any subject, provided such questioning does not prolong the length of the traffic stop. Judge Reinhardt's opinion was based on his reading of two Supreme Court cases: Illinois v. Caballes, 543 U.S. 405 (2005) and Muehler v. Mena, 544 U.S. 93 (2005). Judge Michael McConnell has adopted the same rule for the Tenth Circuit in United States v. Stewart, 473 F. 3d 1265 (10th Cir. 2007). The article explains how Judge Reinhardt and Judge McConnell have misread Caballes and Mena. Their rulings have not only given police the authority to arbitrarily question motorists about criminal behavior, but also directly contradict the Fourth Amendment command that an investigative intrusion must be strictly tied and justified by the circumstances which render its initiation permissible. The judges' interpretation, if not corrected, will undermine Fourth Amendment protections that courts across the nation have uniformly recognized since Terry v. Ohio.
Tracey Maclin, Police Interrogation During Traffic Stops: More Questions than Answers, 31 The Champion 34 (2007)