Differences and similarities of the preliminary ruling procedure of the European Court of Justice, and the advisory opinion of the Permanent Tribunal of Revision of the Mercosur.

The purpose of this paper is to present the reader with a comparative analysis of two judicial tools with similar objectives, under two dissimilar regional integration systems. In order to understand the origin of the differences and similarities of the institute under analysis, we will dive into the cultural, historical, economic and political circumstances, that will ultimately make clear the reasons that explain why the integration outcomes in the Southern Common Market differs from the European one. The final aim is to prove the statement that integration outcomes are highly dependent on regional endogenous properties. The concrete institutions under analysis will present the reader with a concrete case, where the different evolution paths, result in judicial tools of different levels of effectiveness in their respective integration processes.