War of Independence

He proposed a Republican constitution at the 1917 Sinn Féin convention, which was unanimously accepted. In October 1917, he became Chief of Staff of the Irish Republican Army and held that post until March 1918. All through the War of Independence, Brugha continued to run his business as a candle maker. He never went on the run.^[8]

He was elected as a Sinn Féin Member of Parliament (MP) for the County Waterford constituency at the 1918 general election.^[9] In January 1919, Sinn Féin MPs refused to recognise the Parliament of the United Kingdom and instead assembled at the Mansion House in Dublin as a revolutionary parliament called Dáil Éireann. Owing to the absence of Éamon de Valera and Arthur Griffith, Brugha presided over the first meeting of Dáil Éireann on 21 January 1919.^[10]

He had differences with Michael Collins, who, although nominally only the IRA's Director of Intelligence, had far more influence in the organisation as a result of his position as a high-ranking member of the IRB, an organisation that Brugha saw as undermining the power of the Dáil and especially the Ministry for Defence. Brugha opposed the oath of allegiance required for membership of the IRB; in 1919, his proposition that all Volunteers should swear allegiance to the Irish Republic and the Dáil was adopted.^[2]

At a top-level IRA meeting in August 1920, Brugha argued against ambushes of Crown forces unless there was first a call to surrender, but it was dismissed as unrealistic by the brigade commanders present. Brugha also had the idea of moving the front line of the war to England, but was opposed by Collins.^{[citation needed]}

Civil War

On 7 January 1922, Brugha voted against the Anglo-Irish Treaty. During the Treaty Debates, he pointed out that Collins had only a middling rank in the Department for Defence, which supervised the IRA, even though Griffith hailed him as 'the man who had won the war'. It has been argued that, by turning the issue into a vote on Collins' popularity, Brugha swung the majority against his own side. Frank O'Connor, in his biography of Collins, states that two delegates who had intended to vote against the Treaty changed sides in sympathy with Collins. After the vote, the anti-Treaty TDs moved into opposition and Brugha was succeeded as Minister for Defence by Richard Mulcahy.

In the months between the Treaty debates and the outbreak of Civil War, Brugha attempted to dissuade his fellow anti-treaty army leaders including Rory O'Connor, Liam Mellows and Joe McKelvey from taking up arms against the Free State.^[2] When the IRA occupied the Four Courts, he and Oscar Traynor called on them to abandon their position. When they refused, Traynor ordered the occupation of the area around O'Connell Street in the hope of easing the pressure on the Four Courts and of forcing the Free State to negotiate.^[2]

On 28 June 1922, Brugha was appointed commandant of the forces in O'Connell Street. The outbreak of the Irish Civil War ensued in the first week of July when Free State forces commenced shelling of the anti-treaty positions.

Most of the anti-Treaty fighters under Oscar Traynor escaped from O'Connell Street when the buildings they were holding caught fire, leaving Brugha in command of a small rearguard. On 5 July 1922, he ordered his men to surrender, but refused to do so himself. In Thomas Lane he then approached the Free State troops, brandishing a revolver and sustained a bullet wound to the leg which 'severed a major artery causing him to bleed to death'. He died on 7 July, eleven days before his 48th birthday. He had been re-elected as an anti-Treaty TD at the 1922 general election but died before the Dáil assembled.^[11] He is buried in Glasnevin Cemetery.

His wife Caitlín Brugha served as a Sinn Féin TD from 1923 to 1927. His son Ruairí Brugha later became a politician, firstly supporting Clann na Poblachta and later Fianna Fáil, and was elected to Dáil Éireann at the 1973 general election. Ruairí married Máire MacSwiney, the daughter of Terence MacSwiney, the Republican Lord Mayor of Cork who had died on hunger strike in 1920.^[2]