229. The rationale for establishing judicial bodies in EDRSs is that electoral disputes and challenges must be resolved on the basis of the principles of constitutionality and legality, that is, in keeping with the law. They must not be resolved based on political expediency, which often happened with EDR systems that were entrusted to legislative bodies or political assemblies. This has also implied – as experience in comparative law shows – a change in attitude on the part of political parties, election officials and all the other third parties or persons with an interest in a given electoral challenge. Such a system accords priority to institutional means for resolving electoral disputes, and the facts, arguments and evidence that may be produced before a judicial body have had to be brought into line with the technical-legal requirements for their admissibility and consideration. 230. Jurisdiction over a political matter is not the same thing as political jurisdiction, that is, jurisdiction based on political criteria. (One example of political jurisdiction is the jurisdiction that some EDR systems confer on political assemblies or legislative chambers to certify or sit in judgement on the election of their respective members.) A clear-cut distinction needs to be drawn between the two. The fact that a dispute (such as an electoral dispute) is political does not imply that a judicial decision that puts an end to it should be made on the basis of political considerations, convenience or expediency. It must be based on the law. In this way, power is subjugated to reason, not reason to power. Hence the fundamental importance of legal argument in recent times, in both theory and practice, such as that developed by judicial EDRBs. Their importance means that EDRBs and their decisions generally undergo strict scrutiny by the public. The credibility of an EDRS depends on the solid foundation and reasoning of its electoral judgements. 231. The legal oversight undertaken by EDR systems, particularly judicial review, has a number of characteristics which distinguish it from political review. • It has an objective basis, since the standard of review is a pre-existing normative framework, not one determined or chosen by the body that carries out the review. • It is based on legal reasoning and not on political considerations. • It is mandatory; a judicial EDRB must necessarily undertake such a review whenever a matter that falls under its jurisdiction is brought before it. • It is entrusted to an independent and impartial body, which needs to be endowed with the specific technical capacity to resolve legal issues. 87 6. Principles and guarantees of EDR systems independent and impartial, and previously established by law with the proper guarantees, as prescribed by several international human rights instruments (specifically, articles 2(3)(a) and 14(1) of the 1966 International Covenant on Civil and Political Rights).