Question: Which Supreme Commander of the Irish Defence Forces' father was executed by the nascent Irish Free State?

Context articles: President of Ireland
Baldonnel, Dublin
Irish Boundary Commission
Chief of Staff of the Irish Defence Forces
Courts of Justice Act 1924
Irish Republican Army (1922–69)
Robert Erskine Childers
Irish Defence Forces cap badge
Comhairle na dTeachtaí
Constitution of the Irish Free State

The President of Ireland (Irish: "Uachtarán na hÉireann" ] ) is the head of state of Ireland and the Supreme Commander of the Irish Defence Forces.
Baldonnel (Irish: "Baile Dhónaill" , meaning "homestead of the O'Donnels" ), is a townland, and industrial/agricultural area near Clondalkin, Tallaght, Lucan, Saggart and Naas, in west County Dublin.
 It is chiefly known as the location of the headquarters of the Irish Air Corps (Irish Defence Forces) at Casement Aerodrome, Baldonnel, which has been in operation for over 90 years in the locality, first as a RFC then a RAF aerodrome until the creation of the Irish Free State in 1922, when the Irish Air Corps (IAC) took command of the field.
The Irish Boundary Commission (Irish: "Coimisiún na Teorainne" ) met in 1924–25 to decide on the precise delineation of the border between the Irish Free State and Northern Ireland.
 The 1921 Anglo-Irish Treaty, which ended the War of Independence, provided for such a commission if Northern Ireland chose to secede from the Irish Free State, an event that occurred as expected two days after the Free State's inception on 6 December 1922.
 The governments of the United Kingdom, of the Irish Free State and of Northern Ireland were to nominate one member each to the commission.
 When the Northern government refused to cooperate, the British government assigned a Belfast newspaper editor to represent Northern Irish interests.
The Chief of Staff of the Defence Forces (COS) (Irish: "Ceann Foirne na bhFórsaí Cosanta" ) is charged with the executive management of the Irish Defence Forces, and is the most senior military officer of the Army, Naval Service and Air Corps branches.
 The Chief of Staff is appointed by the President of Ireland, who is the Supreme Commander of the Defence Forces, on the recommendation of the Minister for Defence subject to the approval of the Government of Ireland.
 The office of the Chief of Staff consists of his personal staff, a strategic planning office and a public relations section.
The Courts of Justice Act, 1924 was an Act of the Oireachtas (No. 10 of 1924) that established a new system of courts for the Irish Free State (now the Republic of Ireland).
 Among the new courts was the Supreme Court of the Irish Free State, and the first Chief Justice of the Irish Free State was also appointed under the Act.
The original Irish Republican Army (IRA) fought a guerrilla war against British rule in Ireland in the Irish War of Independence between 1919 and 1921.
 Following the signing of the Anglo-Irish Treaty on 6 December 1921, the IRA in the 26 counties that were to become the Irish Free State split between supporters and opponents of the Treaty.
 The anti-Treatyites, sometimes referred to by Free State forces as Irregulars, continued to use the name Irish Republican Army (IRA) or in Irish Óglaigh na hÉireann, as did the organisation in Northern Ireland which originally supported the pro-Treaty side (if not the Treaty). "
Óglaigh na hÉireann" was also adopted as the name of the pro-Treaty National Army, and remains the official legal title of the Irish Defence Forces.
 This article deals with the anti-Treaty IRA that fought against the Irish Free State in the Irish Civil War, and with its successors up to 1969, when the IRA split again.
Robert Erskine Childers DSC (25 June 1870 – 24 November 1922), universally known as Erskine Childers, was a British writer, whose works included the influential novel "The Riddle of the Sands", and a Fenian revolutionary who smuggled guns to Ireland in his sailing yacht "Asgard".
 He was executed by the authorities of the nascent Irish Free State during the Irish Civil War.
 He was the son of British Orientalist scholar Robert Caesar Childers; the cousin of Hugh Childers and Robert Barton; and the father of the fourth President of Ireland, Erskine Hamilton Childers.
The Irish Defence Forces Cap Badge (or "FF badge" as it is sometimes called) is common to all services and corps of the Irish Defence Forces.
 Although principally associated with the Irish Army (Defence Force regulations in fact describe it as "the Army Badge") it is also worn by and appears in elements of the insignia of the Naval Service and Air Corps.
Comhairle na dTeachtaí was an Irish republican parliament established by opponents of the 1921 Anglo-Irish Treaty and the resulting Irish Free State, and viewed by republican legitimatists as a successor to the Second Dáil.
 Members were abstentionist from the Third Dáil established by the pro-Treaty faction.
 Just as the First Dáil established a parallel Irish Republic in opposition to the British Dublin Castle administration, so Comhairle na dTeachtaí attempted to establish a legitimatist government in opposition to the Provisional Government and Government of the Irish Free State established by the Third Dáil.
 This legitimatist government, called the Council of State, had Éamon de Valera as President.
 In 1926 de Valera resigned as President, left the Sinn Féin party and founded Fianna Fáil, which in 1927 entered the Fourth Dáil.
 Comhairle na dTeachtaí, never more than a symbolic body, was thereby rendered defunct.
 In 1930 Cumann na nGaedheal TDs alleged in the Dáil that de Valera had addressed Comhairle na dTeachtaí in December 1926, after the foundation of Fianna Fáil; this was to cast aspersions on de Valera's commitment to the Constitution of the Irish Free State.
The Constitution of the Irish Free State (Irish: "Bunreacht Shaorstáit Eireann" ) was the second constitution of the independent Irish state.
 It was adopted by Act of Dáil Éireann sitting as a constituent assembly on 25 October 1922.
 In accordance with Article 83 of the Constitution, the Irish Free State Constitution Act 1922 of the British Parliament, which came into effect upon receiving the royal assent on 5 December 1922, provided that the Constitution would come into effect upon the issue of a Royal Proclamation, which was done on 6 December 1922.
 In 1937 the Constitution of the Irish Free State was replaced by the modern Constitution of Ireland following a referendum.