In November 2000, Arizona voters passed Proposition 203, a law that replaced bilingual education with a 1-year program known as Structured English Immersion (SEI). Although SEI has little support in the educational or applied linguistics research literature, all English-language learners (ELLs) in Arizona are automatically placed in SEI classrooms. This article examines the effects of SEI on the teachers, administrators, and students at an urban school serving a large number of ELLs. The study found that SEI teachers are largely unaware of the model and unprepared to teach it effectively, that training in SEI strategies has been haphazard, that interpretation of the law's waiver system by State education officials has seriously reduced the number of students eligible for the school's dual-language program, and that forcing English learners into SEI is traumatizing some of them and distressing their parents. The study raises questions about the civil rights implications of the law.