Most sociolegal research on juries and other forms of lay participation in criminal justice has been limited to questions of how lay people make decisions. This article proposes expanding this focus through a conceptually and methodologically novel examination of the recent incorporation of lay decision-makers in Argentina’s criminal justice system. Based on fieldwork conducted in the province of Córdoba, the article follows jurors as they enter the courthouses, unsettle normalized everyday practices and spatiotemporal arrangements, and encounter multiple authorities that define their role and legitimate belonging therein. The work of these multiple entities, the article argues, locates jurors in ambiguous situations between public and private spaces of the courthouses, and ultimately accentuate their alterity vis-à-vis legal professionals. Drawing on an ethnographic approach inspired in actor-network theory and on Mariana Valverde’s sociolegal elaborations of Bakhtin’s notion of chronotope, the article looks at this judicial reform as a site for fruitful examination of law’s multiscalar power dynamics, and it argues that legal institutions be investigated as flexible, fragile, and contingent assemblages of practices beyond their official representations.