This primer explores factors to consider when deciding whether to adopt a second chamber in the constitutional design of its legislature, composition and structural options in designing the second chamber, and the relationship between the two chambers of the legislature. It provides examples of how second chambers are designed around the world.

This document seeks to provide guidance to emerging democracies on the issue of whether the legislative branch should have one chamber, or two. It provides a detailed description of the two structures of the legislature, including their origins, common organization and functions, and their respective advantages. The paper ends with a discussion of the methods of reconciling the functions and powers of a two chamber legislature. These include: giving one chamber the final say, defining the power of the chambers depending on the nature of the legislation, and forcing agreement between the two chambers at the risk of killing the proposed law and/or dissolving the legislature.

This paper, part of a series of working papers on senate reform, provides an outline of comparative features of second chambers in a wide range of federations, in the context of discussion of Senate reform in Canada. It discusses the relationship between federalism and bicameralism, the impact of political parties on the operation of second chambers, and the effect of federal second chambers on the democratic process.