In much of the Western world, the institution of constitutional review has become a central component of constitutional democracy. In the previous chapter, I argued that how and under what circumstances courts are able to exercise influence over the policymaking process poses a puzzle. While many courts have successfully established a claim to the power of constitutional review, most have few means at their disposal to force compliance with their decisions. President Andrew Jackson's apocryphal reaction to the U.S. Supreme Court's decision (written by Chief Justice John Marshall) in Worcester v. Georgia (31 U.S. 515), invalidating attempts by the State of Georgia to assert jurisdiction over the Cherokee Indians provides a poignant illustration: “John Marshall has made his decision, now let him enforce it” (see Smith 1996:518). This lack of formal enforcement powers is potentially significant because implementation of a judicial decision often requires or induces a response by other policymakers. As the examples presented in the previous chapter suggest, governing majorities may be tempted to exploit the opportunity to evade, or at least limit, the impact of unwelcome judicial decisions. How then do courts constrain other political institutions?

Scholars have investigated various bases of judicial authority, including the value that political parties that alternate between government and opposition may place on judicial independence (Landes and Posner 1975; Ramseyer 1994), the fact that courts can help parties to solve Prisoner's Dilemma–type problems (Carrubba 2003), and the informational gain that legislative majorities may achieve from judicial review (Rogers 2001).