Analysis of Arizona's immigration law
In April 2010, Arizona enacted two laws addressing immigration, SB 1070 and HB 2162. These laws added new state requirements, crimes and penalties related to enforcement of immigration laws and were to become effective on July 29, 2010. Before the laws could go into effect, the U.S. Department of Justice filed a lawsuit asking for an injunction against these laws arguing that they are unconstitutional.
http://www.ncsl.org/issues-research/immig/analysis-of-arizonas-immigration-law.aspx