The Statute of Westminster, passed in 1931, granted expanded sovereignty to the Dominions of the British Commonwealth, and permitted the Irish state to amend its constitution and legislate outside the terms of the Treaty.

[4] Pro-Treaty forces won the ensuing election and civil war, and the Free State's new constitution incorporated the monarchial elements mandated by the Treaty.

Under its constitution, the King had functions that included the exercise of executive authority of the state, the appointment of the cabinet, the dissolution of the legislature, and the promulgation of laws.

The representative's title was not actually specified in the Treaty, and Collins considered a number of alternatives, including Commissioner of the British Commonwealth[5] and President of Ireland.

However, no such law was passed during Healy's term of office, and in practice the governor-general never received conflicting advice from Irish and British officials during the existence of the Free State.

It read: I (name) do solemnly swear true faith and allegiance to the Constitution of the Irish Free State as by law established, and that I will be faithful to His Majesty King George V, his heirs and successors by law in virtue of the common citizenship of Ireland with Great Britain and her adherence to and membership of the group of nations forming the British Commonwealth of Nations.The words "allegiance to the Constitution of the Irish Free State" were taken from De Valera's preferred version, which read: "I (name) do solemnly swear true faith and allegiance to the constitution of the Irish Free State, to the Treaty of Association, and to recognise the King of Great Britain as Head of Associated States".

[13] Patrick McGilligan, the Free State Minister for External Affairs, called the Statute of Westminster "the solemn declaration by the British people through their representatives in Parliament that the powers inherent in the Treaty position are what we have proclaimed them to be for the last ten years," and went on to present the legislation as largely the fruit of the Free State's efforts to secure for the other Dominions the same benefits it already enjoyed under the treaty.

Domhnall Ua Buachalla, a republican and former Fianna Fáil TD, was appointed governor-general in late 1932; on his government's advice, he withdrew from all public and ceremonial roles, performing in a perfunctory manner the minimum duties required by the Constitution.

27) Act 1936, swiftly passed by the Oireachtas in response to the abdication, abolished the post of Governor-General and transferred most of the monarch's functions to other organs of government.

However, the constitutional amendment also provided, without mentioning the monarch specifically, for the state to be represented by him in external affairs with other countries and their representatives:[16] it shall be lawful for the Executive Council, to the extent and subject to any conditions which may be determined by law to avail, for the purposes of the appointment of diplomatic and consular agents and the conclusion of international agreements of any organ used as a constitutional organ for the like purposes by any of the nations referred to in Article 1 of this Constitution.The nations referred to in Article 1 were the other members of the British Commonwealth (Australia, Canada, New Zealand, South Africa, and the United Kingdom).

The External Relations Act, adopted shortly after the constitutional amendment, gave life to this provision by providing that:[17] so long as [the Irish Free State] is associated with the following nations, that is to say, Australia, Canada, Great Britain, New Zealand, and South Africa, and so long as the king recognised by those nations as the symbol of their co-operation continues to act on behalf of each of those nations (on the advice of the several Governments thereof) for the purposes of the appointment of diplomatic and consular representatives and the conclusion of international agreements, the king so recognised may … act on behalf of [the Irish Free State] for the like purposes as and when advised by the Executive Council so to do.Thus, for the remaining year of the Irish Free State's existence, the king's role was restricted to diplomatic and foreign affairs – a standard head of state role – but he performed no formal duties in regards to domestic legislation or governance.

[17] In 1937 a new Constitution was adopted on the proposal of Éamon de Valera, establishing the contemporary Irish state named Éire or, in the English language, Ireland.

Article 29 of the new constitution mirrored the amendment to its predecessor passed the previous year, by permitting the state to allow its external relations to be exercised by the king.

Article 29.4.2° provided that: For the purpose of the exercise of any executive function of the State in or in connection with its external relations, the Government may to such extent and subject to such conditions, if any, as may be determined by law, avail of or adopt any organ, instrument, or method of procedure used or adopted for the like purpose by the members of any group or league of nations with which the State is or becomes associated for the purpose of international co-operation in matters of common concern.This provision meant that the External Relations Act continued to have the force of law until the legislature decided otherwise, and so the monarch continued to represent the state abroad when empowered to do so.

[19]Despite de Valera's views, many political scholars consider representing a nation abroad to be the key defining role of a head of state.

The issue seems to have come to a head in 1948 on an official visit to Canada by new Taoiseach John A. Costello, whose Fine Gael party carried the tradition of the pro-Treaty political forces in Ireland.

During a state dinner with the Governor General of Canada, the Earl Alexander of Tunis, an agreement that there would be separate toasts for the King and for the President of Ireland was broken.

Alexander, who was of Northern Irish descent, placed loyalist symbols, notably a replica of the famous Roaring Meg cannon used in the Siege of Derry, before an affronted Costello at the dinner.

Costello biographer David McCullagh has suggested that it was a spur of the moment reaction to offence caused by Alexander at the dinner, although the cabinet members at the time claimed that the decision had already been made and was announced early because it had been leaked to the Sunday Independent.

In the debate in the Seanad Éireann in December 1948 on the law, Costello argued that the bill would make the President of Ireland the Irish head of state.

[33] The opening words of Ireland's superseding constitution of 1937 were "In the Name of the Most Holy Trinity, from Whom is all authority and to Whom, as our final end, all actions both of men and States must be referred", and there was no mention in it of the king or monarch;[34][35] the External Relations Act, the only Irish law referring to the monarch still in force after 1936, called him "the king recognised by those nations [of the British Commonwealth] as the symbol of their co-operation."