Abstract: When the text of a constitution or bill of rights is laid down by its framers, they naturally assume that the words and phrases they use will be understood by the interpreters of the text in the manner the framers themselves understand them. This is more likely to be true at the point of the text's enactment and within the next few years, even decades. However, as time passes, ‘drift’ or ‘slippage’ in meaning1 may occur. A word that had a certain meaning in the past may come to be used in new situations. Section 51(xxi) of the Australian Constitution empowers the Commonwealth Parliament to ‘make laws for the peace, order, and good government of the Commonwealth with respect to… marriage’. In Re Wakim, ex parte McNally,2 Justice Michael McHugh recognized that when the Constitution came into force in 1901, the word marriage bore the meaning ascribed...