147. Similarly, it is common for constitutions to provide that one of the powers of the legislature or one of its chambers is to review the credentials or certifications of those elected to it so that they can take their seats, or to declare who is the president-elect and publish that declaration. At the same time these constitutions establish that a judicial body has jurisdiction or the authority to issue a final and definitive ruling on challenges to election results. Taking into account the practice and constitutional experience of these countries, in this Handbook it is considered that the power of the legislature is a mere formality and that, strictly speaking, the final decision of the EDRS is with the respective judicial organ. 3. The evolution of EDR systems 148. The rise of the first representative democratic regimes was characterized by the adoption of an EDR system that entrusted the final decision on electoral outcomes to legislative assemblies. In the last third of the 19th century, however, a judicial EDR system was established for elections in the UK and the regular courts were given jurisdiction over challenges to legislative elections. Although some countries still give such powers to the legislature, in most this authority was gradually transferred, in the course of the 20th century, to judicial organs in the various democratic regimes – either regular courts as part of the judiciary, constitutional courts, administrative courts or specialized electoral courts. 149. In general terms, there has been an evolution away from EDRSs entrusted to a legislative organ, to mixed EDRSs that combine a legislative body with administrative and/or judicial challenges, to exclusively judicial EDRSs – be they regular, constitutional, administrative or specialized electoral courts or a combination of these. 150. Obviously, the different EDRSs are the result of the legal tradition and evolution of each country, and of the specific social claims of and possible agreements among the various political forces involved. It is difficult to draw any general lessons that can be exported to different historical and political contexts. Nonetheless, a comparative approach makes it possible to identify trends and offers elements of analysis for those interested in electoral matters and for those who are endeavouring to improve all aspects of the electoral process, in addition to identifying successful experience and good practices and the strengths and weaknesses of the respective systems. 151. In general, there has been a marked trend towards the ‘judicialization’ of electoral procedures. Judicial organs are increasingly entrusted with the resolution of electoral conflicts and ensuring that any dispute is resolved lawfully and in keeping with principles of constitutionality, that is, in keeping with the law. This can avoid the broadly discretional criteria and opportunist 62