In some cases two are better than one

THE celebrated 19th-century commentator on the British constitution, Walter Bagehot, reached a negative verdict on bicameralism: “with a perfect lower house it is certain that an upper house would be scarcely of any value”.

Except in federal states, where the case for a second chamber to represent the component units of the federation is strong, it is difficult to justify bicameralism. Advocates of second chambers list two advantages: They facilitate representation of special groups, and they enhance the efficiency of parliament by improving the quality of legislation.

The problem with the representation argument is that if a second chamber is selected on a different basis from the first (which is designed to represent the whole people), it lacks moral authority; but if it is elected on the same basis it may be tempted to challenge the first chamber.