Comparative judicial politics is a growing field in the intersection of political science (more specifically, comparative politics), comparative law and law and economics (in particular, concerning rational choice theory models of judicial behavior). Originally dominated by the U.S. theoretical and empirical literature about federal courts (overwhelmingly influenced by the U.S. Supreme Court), it has expanded to many different courts, jurisdictions and experiences.

a) Models of judicial behavior

There are different theories developed to explain judicial decision making. Formalists take the view that judges simply interpret and apply the law in a conformist view. Formal legal sources matter and judges do conform to precedent and legalist interpretations of the law on many occasions. In a completely different perspective, the attitudinal model sees judicial preferences. It poses that ideology is paramount in explaining how judges vote in collegial courts. However, ideology comes into play within a complex set of various interactions between politics, social experiences, public opinion, judicial philosophies, social norms, modes of behavior in the judiciary and many other considerations that vary across jurisdictions. Finally, agency theorists recognize the importance of judicial preferences but argue that they are implemented considering political and institutional realities.

Whatever model prevails, judicial behavior in any court is the result of personal attributes, attitudes (including policy or ideological preferences), peer pressure, intracourt interaction (a natural pressure for consensus and court reputation; a common objective to achieve supremacy of judicial branch) and party politics (loyalty to the appointer) within a given legal and doctrinal environment.

For example, constitutional judges are appointed by heavily politicized bodies and could be heavily influenced by political parties when these play an active role in the appointment process. Therefore, judicial independence becomes an issue. However, judges are also somehow interested in maintaining a certain status quo that does not hurt the prestige of the court, thereby, keeping some distance from active party politics. In fact, conformity between constitutional judges and party interests can be explained by two different phenomena. First, given the political choice of constitutional judges, they exhibit the same preferences as the party that selects them (i.e., there is an ideological congruence).