The ratio decidendi of Mabo at first sight appears to be very narrow. Assuming that the obiter dicta of Brennan J. are wholly authoritative, then, at first sight, the consequences for the majority of Australian land-holdings are limited. For all his discussion about the need for basing law in wider considerations of justice, and the need for clear intent to be shown on the part of the Crown before native title is extinguished, the fragility of the title created (it can be extinguished merely by an inconsistent grant) means that the judgment can be read as a legitimation of the status quo which clears the Court's conscience. Brennan J. for example, clearly states that pastoral leases will have extinguished native title. An uncertain reservation relates to mining leases, but this seems to be on the ground that all other forms of title, including leasehold, revive after a mining lease expires. As such, the question of native title reviving after a mining lease expires is unresolved. But — and it is a big "BUT" — a good deal depends on the interpretation of the Native Titles Act.
First, the consequences of the judgment will most certainly not be confined to exceptional circumstances. These may include:
1. Those areas where Native Title may still be extant are also those areas where there are extensive mineral deposits.
2. It outlined absolutely no criteria by which Native Title can be identified. The Commonwealth's legislation may, in an attempt to appease certain elements, set wide criteria.
3. All land grants made since 1975, where there is a possibility of Native Title existing, have been thrown into chaos.
4. The High Court appears unlikely to limit the extent of native title.
The majority in Mabo attempt to address possible problems by limiting native title to situations where no extinguishment has occurred and there is a continuing customary association with the land. This is subject to what is stated above and below about the possible widening of the principle in Mabo. The question also arises as to whether the majority's attempt to address this is effectual. Can it achieve these objectives? Why are there no guidelines as to how the existence of native title can be demonstrated? Is this because the rule is so vague that they cannot formulate any clear principles?
There is a deeper problem of the contradictory nature of the High Court ruling: Native title is bound up with "Traditional" rights and use of land but the policy objective is clearly not to enable native title holders to maintain their traditional rights, but to gain economic benefit from land ownership, for example by farming the land, or payment of mineral royalties to title-holders by mining companies. This exercise of economic rights is clearly inconsistent with traditional rights. In other words, once native title is "proven", the land will be used in a manner which would extinguish native title.