Sociologist Anthony Giddens describes modernity as 'the institutions and modes of behaviour established first of all in post-feudal Europe, but which in the twentieth century increasingly have become world-historical in their impact'. Law and the constitution have contributed as much to this 'modernist project' as have other social, political and economic forces. This chapter looks at a group of ideas central to the approach to constitutionalism that is typical of modernist thinking.

The constitution was regarded as the supreme source of law and as a founding document that specified not only the sources of law and a hierarchy of laws, but also the procedures by which laws were made and implemented and by which disputes concerning the law were to be settled. The hierarchy of laws named the constitutional document itself as the supreme source of law, followed by statutes created by parliament, the 'received laws' in place at the time of independence, and customary law and common law.

The legitimacy of the operation of the constitutional system relies on the concept of 'the rule of law': laws are 'legitimate' when they are made by a representative parliament, protected by a court and implemented by an accountable executive. They must also have been generated and issued through agreed and transparent processes. The rule of law is associated with ideas of 'due process' and 'natural justice', which suggest that all decisions must align with a generalised notion of law being applied in a just manner.