This chapter provides a theoretical framework for disentangling the political and legal perspectives on Court behavior. It shows that, indeed, the problem is knotty and how it is impossible to fully separate legal from policy-motivated behavior using only Supreme Court voting data. The knottiness of the problem is exacerbated by the fact that legal factors can exert a decisive effect on a Supreme Court case even when the voting breaks down along ideological lines. This is an incredibly important point. The relentless flow of cases in which justices break down in ideologically sensible ways should not be taken as evidence that justices' decisions are dominated by ideological policy orientations. Instead, the model makes it clear that law can be decisive even when we observe ideological patterns in Court voting. This is especially true when the justices share a consensus about the legal values in question.