<p>Procedural justice theory is premised on the idea that respectful treatment of citizens and allowing them to have a say before the police make their decisions is an unequivocal good. Such foundational assumptions about “voice” and quality of treatment in relation to legitimacy pose problems when verbal conflicts—arguments—occur between the police and the public. We pose two research questions in this paper: 1) Who starts arguments in traffic encounters? 2) How are arguments sustained? We provide an answer by examining arguments that occur between the police and drivers in traffic stops in the US and El Salvador. By illuminating the temporal ordering involved in argument sequences, we argue that the notion of legitimacy and voice are best conceptualized as interactional accomplishments that require the participation of both parties. The implications for procedural justice theory are discussed.</p>