Should Prince William\’s first-born child, if a daughter, become queen or should she be supplanted by a younger brother? This is a question that will be raised at the Commonwealth Heads of Government Meeting in Perth later this month.

British Prime Minister David Cameron told the Westminster parliament that he wrote to the prime ministers of all the other realms of which the Queen is sovereign, and proposed that the rules of succession be changed so that males no longer get precedence over females and heirs will not be removed from the line of succession for marrying a Catholic.

He did not propose changing the requirement that the sovereign be in communion with the Church of England.

Such changes to the law of succession would involve the amendment of a number of historic British Acts, such as the Bill of Rights 1688 and the Act of Settlement 1701. These laws have also become part of Australian law.

So, would the amendment of these laws by the Westminster parliament change the law in Australia about who will be the sovereign of Australia in the future?

Since the enactment of the Australia Acts in 1986, no future British law may extend as part of Australian law. In short, the British cannot legislate to bind Australia any more, even if Australia requested it to do so. Only Australian parliaments can now change Australian laws.

This position is complicated, however, by the commonwealth constitution. It was originally enacted as section 9 of a British Act of Parliament. Section 2 of that British Act states that references to the queen \”shall extend to Her Majesty\’s heirs and successors in the sovereignty of the United Kingdom\”.

There are two ways that this can be read. One interpretation is that it defines the queen or king of Australia as whoever is the sovereign of the United Kingdom.

On this basis, even though the United Kingdom can no longer legislate for Australia, Australia\’s sovereign is determined by reference to the external fact of whoever happens to be the sovereign of the United Kingdom.

The other view is that this section is merely an interpretation clause that makes it clear that references to the queen in the constitution go beyond Queen Victoria to include her successors. It would be a matter for the relevant law to determine who the successor is at any particular time.

On this basis, Australian law would now determine the matter. While the issue was deliberately swept under the carpet during the negotiation of the Australia Acts (because no one wanted to open up another issue for dispute), it is likely that the High Court would today opt for the interpretation approach and decide that it was a matter for Australian law to decide who is the queen of Australia.

As the commonwealth and all the states have anti-discrimination laws, it is likely that all Australian jurisdictions would support changes to the law of succession to remove discrimination against women and Catholics. The question, however, would be who within Australia has the power to enact such a law? At the time the commonwealth constitution was enacted, it was intended that the British would retain control over laws concerning the sovereign. Hence, no power was given to the commonwealth parliament to make laws concerning the royal succession.

Indeed, when the rules of succession were last changed in 1936 upon the abdication of Edward VIII, the federal government took the view that it had no legislative power to enact a law approving the change, so it passed resolutions in both the houses of the commonwealth parliament instead.

Today, the commonwealth will no doubt argue that it has an implied \”nationhood\” power to enact such a law. However, the queen is also a part of state parliaments and plays a fundamental role in state constitutions. Doubts will arise as to whether the commonwealth could unilaterally interfere in state constitutions in this way. The more secure approach would be to use a provision in the commonwealth constitution that allows the commonwealth parliament to enact laws at the request of all the states to exercise a power that only the Westminster parliament could have exercised at the time of federation. This co-operative method would ensure that any changes made by the United Kingdom to the laws of succession to the throne could be validly implemented in Australia as well. So Kate and William\’s first-born daughter would become queen of Australia – if Australia had not by then become a republic.