DEBATES: CHALLENGING EXISTING CONCEPTS Rethinking Bicameral Strength: A Three-Dimensional Approach

Bicameralism remains a common legislative arrangement, providing a classic potential check on political executives. But this potential is not always realised, leading scholars to ask which factors contribute to bicameralism that is ‘strong’. One well-established analysis is that of Arend Lijphart, in his account of majoritarian and consensus democracies. This bases bicameral strength on two dimensions: ‘symmetry’ of the two chambers’ formal powers and ‘incongruence’ of their composition. Other theorists reason in similar ways. But recent British developments, backed by evidence from other states, expose flaws in this approach. A more convincing theory must be ‘three-dimensional’, recognising the centrality of perceived legitimacy to bicameral strength. Legitimacy is fundamental to understanding bicameralism, due both to the composition of some second chambers and to the role of all such chambers in challenging democratically elected first chambers. Lijphart did note that legitimacy affected the dynamics of bicameralism, but its role is both more central, and significantly more complex, than he suggested.