Empirical social science does not take independent judiciaries as a given. Judicial independent might be normatively valuable, and it might even be enshrined in a constitution, but realizing and maintaining an independent judiciary is a long-term political project. Moreover, as Alexander Hamilton pointed out, judiciaries are a relatively weak branch of government, which suggests that their effective independence is fairly fragile.
Broadly speaking, there are two kinds of theories about the political supports for an independent judiciary. The two kinds of approaches are not mutually exclusive, and they are probably both significant to some degree or another. There are lots of specific variations within the broad types. But such theories are concerned with trying to explain the puzzling independence of courts.
One class of theories emphasizes elite support for judicial independence. This has generally been the focus in my work. Political Foundations of Judicial Supremacy, for example, emphasized the strategic calculations of national political leaders like presidents make in finding an independent judiciary to be politically useful. Presidents have benefited from being able to shift blame for unpopular policy outcomes to the unelected courts and to pass off politically contentious policy decisions to ideological allies in the judiciary. Repugnant Laws emphasized how the U.S. Supreme Court has husbanded political authority by cautiously exercising judicial review in a way that does not force a confrontation with ascendant political majorities. Or as I noted in a piece focusing on interaction of the Court and Congress,
