Tijuana is the largest of Mexico’s northern border cities, and despite the US’s dramatic escalation of border enforcement, it remains deeply connected with California by one of the busiest international ports of entry in the world. Drawing on extensive ethnographic research, Passing probes the US-Mexico border’s influence on senses of self and collectivity here. Two publics, it argues, take shape in the shadow of the border. The clase media or “middle class” strives to enact the ideals of liberal publicity: informed, rational debate grounded in an upstanding “I.” The border, however, destabilizes this public profoundly, for as middle-class subjects seek confirmation of their status in the form of a US visa, they expose themselves to suspicions that reduce their projects of selfhood to interested attempts to pass inspection. In contrast, the pueblo, or “the people” as paradigmatically plebeian, imagines itself as composed of actual and potential “illegal aliens.” Instead of the “we” of liberal publicity, this public takes shape via the third person of hearsay: communication framed as what “they say,” what “everyone” knows and repeats. Passing tracks Tijuana’s two publics as they both face off and intertwine in demonstrations, internet forums, popular music, dinner table discussions, workplace banter, personal interviews, and more. Through close attention to everyday talk and interaction, it reveals how the promise of passage and the threat of prohibition together shape Tijuana’s public sphere, throwing into relief the conundrums of self and collectivity born of an age of at once increased transnational flows and fortified borders.