In this article I analyse both the constitutional and the jurisprudential questions mentioned above, taking the statements made by the federal government on occasion of the disallowance of the Civil Unions Act as my point of departure. In relation to both sets of questions, however, I shall go beyond the terms of the questions as set by the Attorney-General and the Prime Minister respectively. With regard to the constitutional law discussion, I shall argue that the central question is not the one of legislative competence raised by the Attorney-General ('Can the Territories, or States, legislate for civil unions or SSM?') but one of consistency between laws passed at different levels of government ('Would State or Territory SSM or civil union laws be consistent with the Marriage Act 1965 (Cth), either as it is now or as it conceivably may be in the future?'). In respect of the jurisprudential questions, since the Prime Minister's moral case for the inherent heterosexuality of marriage was notable by its brevity and lack of sophistication, I will look at the New Natural Lawyers' version of that case, on the assumption (which I will justify) that something like it ultimately informed the Prime Minister's views, and also because I believe that conservative forces in the future are increasingly likely to appeal to New Natural Law Theory when formulating or trying to defend their policies. In responding to the New Natural Lawyers' defence of heterosexual marriage, I will give my own spin to some objections that have already been levelled at it by others, as well as develop novel arguments against it. Given the complexity of the argument and the limited space available, my analysis of both sets of questions cannot be as thorough as it would be had I chosen to concentrate on only one set of questions. But then my goal in this article is neither that of making the definitive case for the constitutional validity of State SSM legislation, nor that of providing a fully developed defence for the morality of SSM and the shortcomings of the New Natural Lawyers' moral vision. Rather, I am interested in beginning to point in the direction of arguments that cast doubt over the legal and moral objections mobilised against SSM in this country: that is, over the uncritical assumption that State SSM legislation would conflict with the federal Marriage Act and over the knee-jerk response that the value of marriage is inseparable from its heterosexuality. The level of my analysis will be pitched in accordance with these 'limited' ambitions.