This chapter specifies the institutional conditions for an autonomous judiciary. It seeks to address the question, when will judges act independently of elected officials? Although scholars agree that judicial autonomy is an essential condition for the rule of law in presidential systems, no consensus exists about the circumstances under which it occurs. We argue that when the executive and legislative branches are united against the courts, the courts have few resources with which to defend an independent course, which may include arbitrating interbranch disputes and upholding rights. In contrast, when significant and sustained disagreements arise among elected officials – such as take place under divided government – judges have the ability to challenge the state and sustain an independent course, with little fear of political retribution.

We seek to demonstrate that a country's position on the judicial autonomy continuum depends on more than so-called parchment barrier guarantees of life tenure (or some other long-term length) or protections against salary reduction. Informal practices that allow elected officials to control the courts often overshadow formal (constitutional) guarantees of judicial independence. Institutionalized subconstitutional practices can shape the incentive structure facing judges so that they are unlikely to oppose government policies. These subconstitutional practices can include withholding funds from the judiciary, imposing limitations on the jurisdiction of the courts, or instituting more drastic measures such as removing judges and court packing. Unified government permits the president and congress to employ these practices or to threaten to do so to subordinate the courts.