By Philip A. Kretsedemas, an associate professor of sociology at The University of Massachusetts Boston
For the past two years, the national debate over police involvement in immigration enforcement has focused on Arizona Senate Bill 1070. When it was first enacted, SB 1070 was widely criticized for the broad discretion it allowed Arizona police to question people about their legal status. Much of this criticism focused on the problem of immigrant racial profiling. Opponents of the bill argued that it opened the door for the indiscriminate interrogation of anyone who looks like an unauthorized migrant.
Even though these complaints figured prominently in the public debate over SB 1070, it is rather telling that they have dropped out of the legal arguments that have been marshaled against the bill. One reason for this curious situation is that complaints about racial profiling and selective enforcement have historically been framed as violations of Fourth Amendment rights. But it also so happens that the legal challenge against SB 1070 is being led by the Department of Justice which, for obvious reasons, is not interested in setting legal precedents that would limit the search and seizure power of the police. The Supreme Court, which is currently deliberating over the DOJ's lawsuit against SB 1070, also has a history of favoring the discretionary powers of law enforcement over Fourth Amendment considerations.
It is important to keep this context in mind when evaluating the legal arguments that are being levied against SB 1070. The DOJ is advancing a finely pitched argument which takes issue with the law making powers of local governments but not the search and seizure practices of law enforcement. It is also bears noting that the DOJ is not opposing local immigration laws on principle. The DOJ supported Arizona's employer sanctions law (penalizing businesses that hire unauthorized migrants) which was subsequently upheld by the 9th Circuit and Supreme Court. The federal government also doesn't seem to be opposed, on principle, to the involvement of police in enforcing federal immigration laws. The Obama administration has actually given state and local police new opportunities to enforce immigration laws. It has only taken issue with local enforcement practices that operate outside of the federal-local enforcement arrangements that have already been authorized by federal law.

veral of the justices appeared to wrestle “with how far states can go in writing immigration laws before they encroach on what is widely regarded as federal turf.”