NPR reports that Arizona Senate Bill 1070 (PDF), the immigration bill that requires anyone who can't produce papers proving they are in the country legally to be arrested, was drafted with the help and influence of Arizona's private prison companies.
"According to Corrections Corporation of America reports reviewed by NPR, executives believe immigrant detention is their next big market. Last year, they wrote that they expect to bring in "a significant portion of our revenues" from Immigration and Customs Enforcement, the agency that detains illegal immigrants."Prison Economics Help Drive Ariz. Immigration Law - NPR