In 1994, California voters went to the polls to pass Proposition 187, a measure designed to deter unauthorized immigration by denying a range of public benefits to the undocumented. Twenty-five years later, undocumented immigration remains a deeply polarizing issue in our country. But if the political discourse seems similar, the civil rights toolkit is not. In an earlier era, equal protection arguments had pride of place, but today, advocates rely heavily on structural and institutional arguments to constrain official discretion.