[3] Proposals to amend the document to recognise Indigenous Australians and to become a republic are the subject of significant contemporary debate.

The most recent referendum occurred on 14 October 2023, in which a proposed amendment to establish an Indigenous Voice to Parliament was rejected.

Multiple motivations existed for increased political co-operation between the colonies; including a desire to regulate inter-colonial tariffs.

A series of conferences to discuss federalism was promoted by the premier of New South Wales Henry Parkes; the first held in 1890 at Melbourne, and another at Sydney in 1891.

A draft constitution was drawn up at the conference under the guidance of Sir Samuel Griffith, but these meetings lacked popular support.

After one failed attempt, an amended draft was submitted to the electors of each colony except Western Australia.

Prior to the bill's enactment, a final change was made to ensure that a right of appeal to the Judicial Committee of the Privy Council from the High Court remained.

Several colonial chief justices and other conservative and financial interests had called for amendments to be made in London, with the British government also objecting to the proposed bill.

[6] After this and some other minor changes, the Commonwealth of Australia Constitution Act became law after receiving royal assent on 9 July 1900.

[7][8] Prior to this Western Australia then agreed to join the Commonwealth to ensure it would be an "original state" alongside the other five colonies.

Some British Imperial laws remained in force, together with those of the Australian colonies although, according to Robert Menzies, "the real and administrative legislative independence of Australia" was never challenged after federation.

[12] A curiosity of the document's history is that the act remains in force as a statute of the UK, despite Australia's subsequent independence.

[13] Under traditional legal theory, the Constitution is binding by virtue of the UK parliament's paramount authority over Australian law; however, various members of the High Court and some academics have expressed the view that the Constitution now derives its legal authority from the Australian people.

[c] As such, to ensure that both positions are held by the same person, any succession laws must be changed in each Commonwealth realm, as was done most recently following the Perth Agreement.

The preamble names all states except Western Australia, mentions God and recognises that the Australian people have agreed to unite under the Constitution and the Crown.

It ends with the standard enacting clause of the United Kingdom, acknowledging the Queen and the UK houses of Parliament as the legal authority of the act.

[30] WHEREAS the people of New South Wales, Victoria, South Australia, Queensland, and Tasmania, humbly relying on the blessing of Almighty God, have agreed to unite in one indissoluble Federal Commonwealth under the Crown of the United Kingdom of Great Britain and Ireland, and under the Constitution hereby established: And whereas it is expedient to provide for the admission into the Commonwealth of other Australasian Colonies and possessions of the Queen: Be it therefore enacted by the Queen's most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the authority of the same, as follows:[31] The Constitution is divided into eight chapters, collectively containing 128 sections.

Section 51 contains a list of topics Commonwealth Parliament is permitted to legislate upon (known as the heads of power).

[35] Some relevant powers of the governor-general are provided here: to summon, prorogue or dissolve the Parliament,[36] and to give or refuse royal assent to federal bills.

This was intentional on the part of the framers of the constitution, however the High Court has found these principles arise as a matter of implication.

For example, the convention under responsible government that the governor-general may only appoint as prime minister a member with the support of the majority of the House of Representatives follows from the requirement that ministers must sit in Parliament[42] and money cannot be spent by the executive government unless authorised by law (passed by the House).

The most famous example of the use of the reserve powers occurred in 1975 where Governor-General Sir John Kerr controversially dismissed Prime Minister Whitlam after the Senate refused to pass supply until an early election was called.

In that episode, the Governor-General Sir John Kerr dismissed the Labor Prime Minister Gough Whitlam, and appointed the Liberal Opposition leader Malcolm Fraser as caretaker Prime Minister on the understanding that he would immediately call an election (which he then won).

This crisis arose due to the breach of the convention that, in the event of a Senate vacancy, the state government would nominate a replacement from the same political party.

[51][52] However, Adrienne Stone has argued that the High Court's purported distinction between a "right" versus a "freedom" is misleading and little more than semantic.

[d] This reflects the commitment to federalism within the constitution, to ensure that any changes to the document cannot be approved solely with the support of the more populous states.

[63] A draft, penned by Howard with the assistance of the poet Les Murray,[64] was heavily criticised by the Labor party, Indigenous leaders and the wider public.

[65] While debate around the preamble was minor compared with the debate around the republic, concerns were raised by opponents about the justiciability of the preamble, especially by those that opposed the inclusion of human rights guarantees in the document and by those who felt the court had become unduly "activist" in the wake of the Mabo decision.

[68] At the same time, a limitation on including all Indigenous Australians in population counts for constitutional purposes was removed, which in 1967 was relevant only to section 24.

In his Closing the Gap speech in February 2020, Prime Minister Scott Morrison reinforced the work of the Referendum Council, rejecting the idea of merely symbolic recognition, supporting a voice co-designed by Aboriginal and Torres Strait Islander people, "using the language of listening and empowerment".