How many shapes can a parliament take? Unicameral, bicameral and even tricameral arrangements stem from the peculiar constitutional history a country has experienced, even though there are common traits behind the choice of a certain parliamentary structure. The chapter deals with the cases of unicameralism and ‘masked’ bicameralism presented in the main chapters of Part II and tries to identify the conditions under which a second chamber can be deemed in existence as well as the pros and cons of having functional bicameralism or second chambers ‘lookalikes’ in place. After briefly reviewing examples of multi-chamber parliaments and of successful abolition of second chambers, the chapter engages with the cases of Bulgaria, Peru and Ireland as paradigmatic experiences of the tension between unicameralism and bicameralism.

In today’s world of crisis of liberal constitutionalism, what are the virtues and pitfalls of bicameralism? In other words, to what extent does bicameralism constitute a bulwark against the ‘democratic decay’ or, rather, is it (a small) part of the problem?

At first glance it appears that comparative constitutional scholars show limited interest toward parliaments, preferring courts by far (Waldron 1999; Bauman and Kahana 2006; Bar-Siman-Tov, Chapter 9 in this volume). Unlike the case of comparative political studies, which abound in classifications and typologies of legislatures (Polsby 1975; Mezey 1979; Norton 1996), no such categorizations have been developed in law. However, when looking more closely at comparative legal studies on parliaments it becomes clear that they are mainly focused on parliamentary procedures and their rules, on the constitutional implications they have on the status of MPs, on individual rights, on the quality of legislation and as guarantees of the separation of powers. Sometimes it is difficult to disentangle the contribution of comparative legal scholars from those doing comparative politics. The research on parliaments appears to a great extent to be the result of a joint effort (Rozenberg and Thiers 2018), even though it is certainly true that some themes like parliamentary immunities and the relationship between parliaments and courts in enforcing the Constitution have been eminently considered by constitutional law scholars.