According to many scholars, the rejection of the Constitutional Treaty and the disappointment caused by the contents of the Lisbon Treaty –- defined by Somek (2007) as a mere post-Constitutional Treaty – mark the failure of any possible constitutional ambition for the European Union (EU). In this paper I argue that the so-called constitutional “failure” of the EU is actually a confirmation of the current constitutional nature of the EU rather than proof of the impossibility of transplanting the constitutional discourse to the EU level. This point can be challenged both from a theoretical point of view – by describing the EU as an example of “evolutionary constitutionalism” – and a pragmatic one (i.e., looking at the functioning of concrete constitutional experiences), I will focus my paper on this second point, insisting on comparative argument. The research question of this work is: Can we compare the “constitutional crisis” of the EU to the constitutional difficulties encountered by other multinational experiences? My idea is that the latest attempts at amending the EU treaties – the period of the “Conventions” – can be traced back to the genus of mega-constitutional politics and starting from this parallelism I argue that the so-called constitutional “failure” of the EU is actually a confirmation of the current constitutional nature of the EU rather than the proof of the impossibility of transplanting the constitutional discourse to the EU level