In late June 2012, the Supreme Court struck down three provisions of Arizona’s SB 1070 and left a fourth vulnerable to future legal challenge. As has been well documented, the Court’s rejection of SB 1070 tipped the balance in favor of federal enforcement and away from state and local enforcement of the immigration laws. But this essay explores a less obvious consequence of the Court’s decision: its implications for the viability of a critical federal enforcement mechanism: the immigration “detainer.” An immigration detainer is a piece of paper that federal immigration officials send to state and local jails requesting that they continue holding an individual for up to 48 business hours after he or she would otherwise be released, so that agents of U.S. Immigration and Customs Enforcement (ICE) can investigate the person’s status and assume custody if necessary. Also known as immigration “holds,” detainers are the key enforcement mechanism behind federal enforcement initiatives like the Criminal Alien Program and Secure Communities. There has been considerable confusion as to whether a detainer is a mere request that ICE be notified of a suspected immigration violator’s impending release, or a command by ICE that state or local officials hold a prisoner for ICE beyond the time the prisoner would otherwise be released. Independent of that question, however, the Court’s decision in Arizona v. United States identifies a more fundamental problem: that detainers may violate the Constitution and federal statutes even when honored on a voluntary basis.

This two-part series highlights the findings of the Migrant Border Crossing Study—a binational, multi-institution study of 1,110 randomly selected, recently repatriated migrants surveyed in six Mexican cities between 2009 and 2012. The study exposes widespread mistreatment of migrants at the hands of U.S. officials in the removal system. Part I: Migrant Mistreatment While in U.S. Custody This report focuses on the mistreatment of unauthorized migrants while in U.S. custody. Overall, we find that the physical and verbal mistreatment of migrants is not a random, sporadic occurrence but, rather, a systematic practice. One indication of this is that 11% of deportees report some form of physical abuse and 23% report verbal mistreatment while in U.S. custody—a finding that is supported by other academic studies and reports from non-governmental organizations. Another highly disturbing finding is that migrants often note they are the targets for nationalistic and racist remarks—something that in no way is integral to U.S. officials’ ability to function in an effective capacity on a day-to-day basis.

Since the last major legalization program for unauthorized immigrants in 1986, the federal government has spent an estimated $186.8 billion on immigration enforcement. Yet during that time, the unauthorized population has tripled in size to 11 million.