External bias. External bias is derived from the influence that political bodies (such as parties, the assembly and government) are able to exert on the judiciary.
--> Principle of judicial independence. But this may be compromised (because of close involvement with political bodies).

Internal bias. Internal bias comes from the prejudices and sympathies of judges themselves  (particularly the ones that intrude into the process of judicial decision-making).

Socialist critique on judiciary: it articulates the dominant values of society  and so acts to defend the existing political and social order.

The existence of a written constitution enhances the status of the judiciary, giving it the power of judicial review.
In the absence of a codified constitution, judges lack a legal standard to measure the constitutionality of political acts and government  decisions.