In immigration law as in other areas of legal scholarship, it is hard enough to find answers, but it is even harder and more important to pose the right questions and to understand the assumptions and frames of reference that define the field. For immigration law in particular, one of the basic choices is whether to adopt the traditional definition--as addressing whether noncitizens are allowed to enter and stay--or to embrace a broader range of questions about immigrants' rights, citizenship, and the integration of immigrants.

With the definition of the field up for grabs, the contributions of legal scholars are especially valuable if they not only search more deeply for answers to fundamental questions of law and policy, but also prompt us to consider why the questions matter in the first place. The Second-Order Structure of Immigration Law by Professors Adam Cox and Eric Posner does both, the first quite explicitly but the second only obliquely. This Essay fills out the picture painted partially by Second-Order Structure, with a particular effort to identify its unstated assumptions, to examine those assumptions, and to explain why they make a difference...