Irish Republican Army 1919-1922

The Irish Republican Army of the period 1919 to 1923 was a revolutionary paramilitary organisation central to the struggle for Irish independence and the political upheavals that followed. Emerging from the Irish Volunteers, it fought a guerrilla campaign against British rule during the Irish War of Independence and split over the Anglo–Irish Treaty, leading to the Irish Civil War. Often referred to retrospectively as the “Old IRA”, the organisation represented the military wing of the Irish Republic proclaimed in 1916 and reaffirmed by the First Dáil in 1919.

Origins and Reorganisation

The roots of the IRA lay in the Irish Volunteers, founded in November 1913 in response to political tensions surrounding Home Rule. The Volunteers took part in the Easter Rising of 1916, an armed insurrection aimed at ending British rule in Ireland. The Rising was suppressed and thousands of members were imprisoned or interned, causing the temporary collapse of the organisation.
The Volunteers were reorganised in 1917 following the release of internees and prisoners. At the October 1917 Army Convention held in Dublin, Éamon de Valera was elected president, with Michael Collins appointed Director of Organisation and Cathal Brugha made Chairman of the Resident Executive, effectively Chief of Staff. Following Sinn Féin’s victory in the 1918 general election, the First Dáil assembled and declared the establishment of the Irish Republic. The Volunteers were recognised by this new parliament as the legitimate army of the Republic.

Transition to the IRA

By late 1919, the name Irish Republican Army came into common use, reflecting the Volunteers’ acceptance of the authority of the Dáil and their role as the armed forces of the Irish Republic. Even earlier, in 1917, some Volunteers charged with illegal drilling had described themselves as IRA soldiers and refused to recognise British courts, insisting on being treated as prisoners of war.
A dispute persisted within the organisation’s upper ranks over control and strategy. While Brugha, as Minister for Defence, was nominally the senior figure, Collins’ influence stemmed from his organisational role in the IRA and his position on the Supreme Council of the Irish Republican Brotherhood. De Valera viewed Collins’ power as flowing disproportionately from the secretive IRB. Both Brugha and de Valera advocated large-scale, conventional military engagements for their propaganda impact, though these suggestions were not adopted by Collins and Richard Mulcahy. Many Dáil members, including Arthur Griffith, preferred passive resistance over armed confrontation.
The Dáil formally accepted responsibility for IRA activity only in April 1921, mere months before the truce that ended the War of Independence. In practice, Collins commanded the guerrilla campaign, with Mulcahy as his deputy. Although able to issue orders and provide arms, headquarters exerted limited control over local commanders due to the decentralised nature of guerrilla warfare.

Social Composition and Internal Organisation

The IRA claimed around 70,000 members, but only about 3,000 were actively engaged in sustained fighting. The organisation divided its membership into three categories:

• Unreliable members, who contributed little,
• Reliable members, who provided support and occasional combat,
• Active members, who fought full time.

Active guerrillas were disproportionately skilled tradesmen, students, and urban workers, while farmers and fishermen were underrepresented. Many active members were in their late teens or early twenties, and most were unmarried, reflecting the demands of life on the run. Although non-sectarian in principle and open to all Irish people, the IRA’s active membership was overwhelmingly Catholic, with only a handful of Protestant volunteers.
A small but significant number of participants were First World War veterans who applied their military experience to the IRA’s guerrilla strategy. Women played important roles within the republican movement, particularly in intelligence, logistics, and communications, though they did not serve as combatants within the IRA.

Guerrilla War and Strategy

The IRA campaign against the Crown forces began in January 1919 with the Soloheadbeg Ambush, when members of the Third Tipperary Brigade seized explosives and killed two RIC constables. The guerrilla war developed through distinct phases:

• 1919: sporadic engagements while the IRA reorganised nationally and locally,
• 1920: escalation of ambushes, raids, and attacks, particularly after reprisals by Crown forces,
• 1921: intensified operations leading up to the truce of July.

Although there were nominally 100,000 Volunteers after the conscription crisis of 1918, fewer than 15,000 took part in the campaign. Local commanders such as Tom Barry in Cork, Liam Lynch, and Seán Mac Eoin in Longford led highly effective flying columns responsible for some of the war’s most successful operations.
The IRA distrusted many Irishmen who had served in the British Army during the First World War, fearing infiltration. However, figures such as Emmet Dalton, Tom Barry, and Martin Doyle proved notable exceptions, bringing valuable tactical expertise.
Strategically, the guerrilla campaign sought to undermine British authority through attacks on Royal Irish Constabulary barracks, ambushes of military patrols, destruction of infrastructure, and targeted assassinations. The decentralised structure often left local brigades to plan and execute operations with minimal direction from headquarters.

Split over the Anglo–Irish Treaty

The end of the War of Independence came with the signing of the Anglo–Irish Treaty in December 1921. Its acceptance by the Dáil led to a deep schism within the IRA. Those who supported the Treaty formed the core of the new National Army of the Irish Free State. However, a majority rejected the settlement, viewing it as incompatible with the republican ideals of 1916 and the sovereignty of the declared Irish Republic.
In March 1922, anti-Treaty officers held an Army Convention and repudiated the authority of the Dáil in accepting the Treaty. The anti-Treaty faction subsequently established its own Army Executive, claiming legitimacy as the true government of Ireland.
The Provisional Government, formed under the Treaty and recognised by Britain, began to assume administrative and military responsibilities. De Valera resigned from the presidency of the Irish Republic after the Treaty’s approval and unsuccessfully sought re-election. He continued to advocate for an external association arrangement, though the concept did not gain widespread acceptance.

Civil War and Aftermath

The disagreement over the Treaty escalated into armed conflict in June 1922, with the outbreak of the Irish Civil War. The National Army, equipped with British-supplied artillery and armoured vehicles, seized Dublin and then launched operations against anti-Treaty strongholds in the south and west.
Although anti-Treaty units continued guerrilla resistance after the loss of urban centres, their campaign diminished through 1923. In May of that year, the anti-Treaty IRA leadership issued an order to “dump arms”, ending organised opposition to the Free State. The civil war’s outcome cemented divisions that shaped the political landscape of Ireland for decades. The pro-Treaty movement evolved into the party now known as Fine Gael, while the bulk of anti-Treaty republicans formed Fianna Fáil. A minority continued to adhere to uncompromising republican principles, contributing to the later development of Sinn Féin.