Comparative legal method is of importance in any aspect of the development of European constitutionalism. When in the course of interpretation constitutional jurisdictions look beyond the classical methods – textual, systematic, historic, teleological – and include in their decision-making process arguments sourcing from case-law of other courts with constitutional jurisdiction, this leads to an exchange of arguments and the improvement of common values, and, in the end, to the development of supranational constitutionalism based on shared values.
In our study we use the following terms:
“method” – for the purposes of the present text to be understood as a style of referring to decisions of other constitutional jurisdictions or their usual practice.
“foreign” – courts in as much as their headquarters are situated outside of the country.
“constitutional courts” – hereinafter all courts, tribunals, councils with constitutional jurisdiction would be considered as constitutional courts, including supranational courts (CJEU and the ECtHR) which in their case-law deal with constitutional matters or use specific constitutional rhetoric. The CJEU and the ECtHR will be referred to as “constitutional courts” or court with constitutional functions for the purposes of the present research.
“quoting” – since quoting is considered merely as pointing out, referring to, the process of finding out or establishing the foreign case-law, as it is done in international private law, for example, falls out of the scope of the present research. However, it is worth noting in brief that the main sources of case-law are official webpages of constitutional jurisdictions, and their official editions, search results in CODICES, official formal requests through the forum of the Venice Commission, informal inquiries that are based on personal contacts between justices and finally, secondary sources such as scientific research which quotes case-law. Habitually, when the source of information is secondary, justices request the staff for the original decision itself in one of their working languages no matter how distinguished the author of the scientific paper/research/book is.