Kelly Downs & Delmer Rasmussen 
Illegal Aliens [PDF ebook] 
Enforcement and Restrictions by State and Localities

This book discusses the power and ability of state and local authorities to assist in the enforcement of federal immigration law through the investigation and arrest of persons believed to have violated such laws. It describes federal statutes that expressly permit state and local police to enforce immigration law directly, and analyzes major cases concerning the ability of states and localities to assist in immigration enforcement.