Arizona's notorious law targeting illegal immigrants goes under the legal microscope in the nation's highest court today. At issue is the power of the federal government over states' rights and whether the law encroaches on federal authority over immigration policy. Arizona sparked a huge national debate two years ago when it took immigration into its own hands, passing the controversial law known as SB 1070. Several other states followed suit with laws of their own, legal challenges were filed, and now four parts of the law are under consideration by the Supreme Court. How will this case affect similar laws in other states? What impact will a court ruling have in an election year? At a time when immigration from Mexico has fallen sharply, is there even a need for such laws?