This historical case study focuses on policy making at the state level by analyzing the development of a new policy for English language learners (ELLs) in Arizona. "New institutionalism" is used as a framework, with political culture and educational regimes acting as environmental factors affecting state policy choices. Key events occurred between 1992, when "Flores v. State of Arizona" challenged the funding of instruction for ELLs, and 2006, when the legislature adopted a law creating an English Language Learners Task Force that was to develop a 4-hour-per-day structured English immersion (SEI) program for ELLs. Analysis indicates that the new policy is consistent with the state's traditionalistic political culture and emerging neoliberal political regime and with the mythical role of an immigrant's learning of English as a mark of becoming an American. Policy leaders used and altered the state's political institutions to advance their objectives. The study concludes with a four-prong test for assessing the fit of proposed policies with the current political context of the state. (Contains 3 tables and 3 notes.)