From the introduction: "This report examines the interplay between the federal government (i.e., ICE) [U.S. Customs and Immigration Enforcement] and state and local jurisdictions in enforcing immigration law, with a specific focus on noncitizens who have been convicted of a crime. It explores federal resources available to state and local law enforcement agencies that cooperate with ICE to enforce immigration law. The report begins by briefly discussing the evolution of the cooperation between the federal government and local law enforcement in carrying out federal immigration policy. It then discusses current administrative efforts to involve state and local law enforcement in enforcing immigration law. A brief discussion of resources dedicated to these efforts follows. The report concludes with a discussion of select issues and an analysis of possible policy approaches for Congress."
CRS Report for Congress, R44118
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html