The paradox of constitutional persistence deals with the historical phenomenon of the persistence of what modern political scientists denote as the "Medieval Constitution"" in some, but not all, of medieval Europe. In essence, the paradox forces political scientists to answer for the occurrence of the constitutional order of kings and consultative assemblies such as parliaments, in some but not all cases, throughout Europe. Let us refer to these consultative assemblies as estates, as Thomas Ertman does in "Birth of the Leviathan". The estates are consultative assemblies consisting of members from a variety of backgrounds including those of the clergy, nobility, and third commons (privileged towns people), who in effect, consult with the territorial ruler on topics most commonly surrounding the issues of taxes, war, religious order. As we will see, although the territorial ruler holds a wealth of advantages over the estates, advantages such as popular support, procedural power, and the ability to produce privilege, the estates can and will persist in cases where the inherent structural organization of the estate allows for the estate to gain some basis of support within the territory it claims to represent. .
Despite the various explanations available to explain the phenomenon of constitutional persistence of estates in some but not all of Europe, we will find that only institutional design leads us to the most feasible explanation. That is to say, analyzing the ideas behind institutional design in order to properly explain the paradox of constitutional persistence leads us to the conclusion that estates will persist where the estates have, as Ertman alludes, high cohesion and low bargaining costs from the standpoint of the territorial ruler. High cohesion and low bargaining costs incidentally result from the estate's organization, which also gives rise to increased social support, and as we will see, is the most effective means for the survival of the estates.