The Second Dimension of the Supreme Court

Describing the justices of the Supreme Court as ‘liberals’ and ‘conservatives’ has become so standard — and the left-right division on the Court is considered so entrenched — that any deviation from that pattern is treated with surprise. Attentive Court watchers know that the justices are not just politicians in robes, deciding each case on a purely ideological basis. Yet the increasingly influential empirical legal studies literature assumes just that — that a left-right ideological dimension fully describes the Supreme Court. We show that there is a second, more legally-focused dimension of judicial decision-making. A continuum between legalism and pragmatism also divides the justices, in ways that cuts against ideological preferences. The second dimension is systematic and significant, occurring in multiple different legal areas, and in consistent patterns. Seen in this way, the justices and their decisions can be understood in more complex terms, not just as ideological flag bearers, but as jurists who regularly have to choose between legal methodology and outcome preferences. In two dimensions, different patterns of coalitions emerge: in the second dimension, it is the Chief Justice and Justice Sotomayor, not Justice Kennedy, who sit at the median of the Court, and decide the balance of power.