The Proportionality Principle and the Kable Doctrine: A New Test of Constitutional Invalidity?

Abstract

In Kable v Director of Public Prosecutions (NSW) the High Court of Australia declared that the requirements of Chapter III of the Australian Constitution prohibited a State legislature from conferring powers on a State court that were repugnant or incompatible with their status as repositories of federal judicial power. This was a significant constitutional watershed; it had never previously been suggested that the protections contained in Chapter III applied to State courts. Recent applications of Kable, however, have given rise to concerns that the principles to be derived from that case are unclear. This is a serious deficiency given that State legislatures, not bound by a separation of powers doctrine at a State level, may choose to confer important decision-making functions on non-judicial bodies. This article explores whether a bipartite inquiry, such as that employed in the rights jurisprudence in both England and Strasbourg, may clarify the meaning and scope of the principle enunciated in Kable. It commences by formulating a mode of inquiry which is intended to assist courts in determining whether a legislative act impairs the institutional integrity of a State court. It then argues that the principle of proportionality should be employed to determine whether a prima facie impairment may nonetheless be excusable. Such a conclusion would be reached where it can established that the legislative act is necessary in a democratic society, in the sense that it addresses a pressing social need. The introduction of this limited ground of justification promotes greater clarity and ensures that an appropriate balance is maintained between State legislative autonomy and the institutional integrity of State courts.