This Article explores the importance of the Civil Rights Act of 1870 to the current debate over immigration federalism and the preemption of state and local immigration laws under the Supremacy Clause. The 1870 Act, enacted by the Reconstruction Congress after the Civil War, prohibits discrimination on the basis of “alienage.” The Article shows that the Act’s protections are an essential component of the federal framework limiting sub-federal immigration laws. In Arizona v. United States, the Supreme Court found key parts of Arizona’s SB 1070 immigration enforcement act preempted. The Court focused on the federal government’s broad authority to enforce the immigration act, to set enforcement priorities, and to determine the terms and conditions for the admission and expulsion of foreign nationals. The author refers to this as the “immigration control” basis for preemption.
The Article explains that the immigration control element is important but incomplete. That focus omits consideration of the separate and additional source of federal primacy derived from the Civil Rights Act of 1870 that the author calls the “immigrant equality” basis for preemption. The Article discusses the origins of the Act’s protections, their subsequent codification, and the Supreme Court’s reliance on the Act’s anti-discrimination mandate in immigration preemption cases over the course of nearly a century. The Article argues that recognizing immigrant equality as a source of federal supremacy has significant consequences for immigration federalism. The equality principle assesses the discriminatory consequences of sub-federal immigration measures and draws a fundamental distinction between measures that further immigrant equality (often referred to as “sanctuary” ordinances) and laws that threaten to engender discrimination (like SB 1070). The Article concludes that robust federal supremacy barring punitive immigration enforcement laws can easily coexist with ample leeway for states and localities to adopt immigrant protection laws that safeguard non-citizens in municipal life.