In June 2015, Donald Trump announced his candidacy in the 2016 election for president of the United States. In the speech accompanying this announcement Trump offered several gross and sweeping misrepresentations of immigrants to the US, suggesting, ‘They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people’ (Associated Press, 2015: n.p.). Trump’s views disturbingly articulate widely held ideas among a segment of the US general public that casts migrants as criminals and equates migration with illegality. Where have these associations come from? How are criminality and illegality mobilised in US immigration enforcement? How do they link immigration to larger carceral regimes? How are criminality and carcerality materialised in detention practices? What are the broader implications for understanding and researching the mobility of carceralisation in society as a whole? In this chapter we consider these questions drawing insight from scholarship on carceral geography (Loyd et al., 2012; Moran, 2015; Moran et al., 2013; Peck, 2003; Philo, 2012), which investigates issues of human security with a particular focus on spaces used to detain and incapacitate supposedly problematic groups. We also draw upon work by ‘new mobilities’ scholars including Cresswell (1999, 2010, 2012) and Sheller and Urry (2006). Finally, we employ research and reports on migrant detention in the US (ACLU, 2012; Doty and Wheatley, 2013; DWN, 2015; Freeman and Major, 2012; HRW, 2009; Meissner et al., 2013) as well as our ongoing research on the internal micro-economies of migrant detention (Conlon and Hiemstra, 2014; Hiemstra and Conlon, 2016). We argue that criminality in the context of immigration law and immigration detention is mobilised as an iteration of the carceralisation of society (Peck, 2003). Not only does this process shape problematic conceptions of migrants and mobility across borders like those articulated by Donald Trump and his retinue. In addition, echoing McCann (2010), who identifies a need to examine the ‘mobility of ideas’ (cited in Cresswell, 2012: 651), we propose that the movement of carceral ideology and practices from spaces of confinement, such as prisons and immigrant detention, into wider public spheres has profound implications for understanding the ‘politics of mobility’ (Cresswell, 2010) and the production of exclusion for other social groups in contemporary

society. We also demonstrate how tracing the evolution of hegemonic ideas can deepen understanding in carceral mobilities scholarship.