Irish War of Independence (1919-21)

The 1918 General Election for the House of Commons in Westminster is regarded as a defining act of Irish nationalism and self-determination. The Irish Parliamentary Party (IPP), which had dominated Irish politics, held a mere six seats. Sinn Fein, on the other hand, won seventy-three of the one hundred and five seats—or, seventy percent of the public’s vote. Sinn Fein had campaigned for an immediate separation from Great Britain, arguing historic abuses and discrimination.[1] What drove voters to the arms of Sinn Fein was the early 1918 conscription crisis. In the last year of the First World War, Great Britain was in desperate need of men. To raise troops, Prime Minister Lloyd George was pressured to call for mandatory Irish conscription. The IPP remained popular, but it was this crisis that pushed the public away from parliament in protest.[2]

The election was called only ten days after the end of hostilities, and a peace conference was arranged for next year, where the victors of the First World War would convene at Versailles. Not only was the election was an opportunity to send a message to London, but the men elected would be responsible for representing Ireland in Versailles.[3]

A perfect storm was brewing: the ‘16 Easter Rising, which began to shift public opinion in favor of radical republicanism; President Wilson’s influential ideal of self-determination and the right of a peoples to establish their own sovereign nation; British mismanagement, the tragedy of Home Rule, and the early 1918 conscription crisis; and, now, Sinn Fein’s landslide election victory on 21 November, 1918.

In January 1919, the newly-elected Sinn Fein representatives refused to take their places in Westminster and on 21 January, they formed the first Irish Assembly, the Dail Eireann. That same day, two members of the Royal Irish Constabulary (RIC)—a police force in Ireland created by the British—were killed in Soloheadbeg in COunty Tipperary. The Irish War of Independence had begun. The Dail declared independence from Great Britain and appealed for international recognition. By then members of the Irish Republican Brotherhood (IRB) and the Irish Volunteers had joined Sinn Fein; and they wanted war. [4]

The IRB and the Irish Volunteers formed the armed wing of Sinn Fein, the Irish Republican Army (IRA). Though the IRA was, as the name suggests, the nation’s army due to a short supply of men, weapons, and ammunition, the group operated more like a terrorist organization. At the suggestion of the ambitious Michael Collins, the IRA resorted to guerrilla tactics, operating as mobile killing units. The IRA’s attacks focused on the RIC—a symbolic instrument of British imperialism in Ireland, but also an accessible source of arms.[5]

For the first year of the war, the IRA was successful against the poorly trained RIC. Until the 1880s, the RIC was a highly trained and well-organized police force. Officers often integrated well into their communities, and a majority of the members were Irish Catholics; this was especially the case in the more rural counties of Ireland—primarily in the south and south-west. Yet, the British government rightly felt that the resources being used to train the RIC were being wasted. Officers were respected, often spending their free time with locals at the town pubs; and there was little evidence to believe that an armed force would be necessary in the future—especially given that Home Rule and the IPP was still extremely popular. By the time of the War of Independence, however, the RIC was incredibly unprepared for what was coming. [6]

Officers were shot leaving mass, in their homes, at the RIC barracks, and at the pub. The IRA justified their actions arguing that they were in a war, and the murders went largely unpunished. In March of 1920, the brutality of the war escalated when the British sent the Black and Tans—a group of temporarily recruited constables to reinforce the RIC. Members consisted of primarily unemployed veterans with extensive military training and experience. Later that same year, the British formed the Auxiliary Division of the Royal Irish Constabulary. The Auxiliaries were a highly mobile paramilitary unit formed to combat the IRA. Their tactics were brutal and the men heavily armed. These men would commit the worst atrocities of the war. Frustrated of seeing their friends and colleagues murdered, the RIC retaliated. This retaliation, called reprisals, would come after an officer was killed. For example, if an officer was killed by an IRA patrol unit, the RIC may then blow up the town’s creameries. Or frighten and kill locals. Or set homes on fire. Reprisals were brutal and the victims were often innocent civilians. [7]

The IRA took advantage of the brutal reprisals, using them as fuel for propaganda to consolidate public support. Yet, the public was not fooled. Many recognized that these reprisals would not occur if the IRA had not murdered RIC officers. But what alternative was there? Home Rule was dead in the water and the British were at the root of so much suffering. Much of the public, including the Catholic clergy, supported Irish nationalism and independence, but were opposed to the violent means of achieving it. [8]

The final year of the war became its bloodiest. On 21 November 1920, Michael Collins’ squad attacked twenty military intelligence officers in Dublin. Fourteen were killed, and six were wounded. Later that day, a group of Auxiliaries massacred innocent civilians during an Irish football match at Croke Park. Fourteen were killed, and over sixty were wounded. Afterwards, the British declared martial law, sanctioning a program of official reprisals and insurgents were systematically hunted. In response to this escalation, the IRA became more ruthless in their attacks. Nationalists sought to create a united Ireland—which would include the six counties of Ulster—but the brutality of the war deterred them further. Ulster was already decidedly against Home Rule as they feared an eventual separation from Great Britain. In light of this, the IRA was arguably the least likely candidate to convince the population of Ulster to join an independent Ireland.[9]

The war was taking a toll on everyone . An estimated 1,400 people were dead, including more than 600 members of the British security forces and over 700 civilians and IRA members. In July 1921, a truce was negotiated and on 6 December a treaty was signed. In 1922, all British forces were withdrawn from southern Ireland, and it appeared as though peace was finally within reach.[10]

[1] “The 1918 General Election,” Dail100 of the Houses of the Oireachtas, accessed March 10, 2026, https://www.dail100.ie/en/long-reads/the-1918-general-election/.

[2] John Bruton, “The 1918 Election and its Relevance to Modern Irish Politics,” Studies: An Irish Quarterly Review 108, no. 429 (2019): 93.

[3] Bruton, “The 1918 Election,” 94.

[4] “Irish War of Independence,” National Army Museum, accessed March 10, 2026, https://www.nam.ac.uk/explore/irish-war-independence.

[5] W.J. Lowe and E.L. Malcolm, “The Domestication of the Royal Irish Constabulary, 1836-1922,” Irish Economic and Social History 19, no. 1 (1992): 28-29.

[6] Lowe and Malcolm, “The Domestication,” 33.

[7] Robert Kee, The Green Flag: A History of Irish Nationalism (Penguin Books, 1972), 669-677.

[8] Kee, The Green Flag, 684-690.

[9] “Irish War of Independence.”

[10] “Irish War of Independence.”