The self-proclaimed Irish Republic , which fought the 1919 – 21 War against the British authorities , established its own republican courts . In summer 1920 , when a County Meath republican court sentenced a man to death for murder , the sentence was referred to the Dáil ministry , which decided to uphold it , although Constance Markievicz was reluctant . The Irish Republican Army was empowered by the First Dáil to court-martial and execute pro-unionist civilians for such crimes as " spying " and collaboration . The procedures at such trials depended on the local IRA leadership ; many were kangaroo courts imposing summary justice . Besides executions , IRA members also carried out combat operations , assassinations , extra-judicial killings , and personally motivated murders , with varying levels of sanction from the republican leadership ; historians have commented that the dividing lines between these categories can be blurred and contentious ; an example being the 1922 Dunmanway killings
Dunmanway killings
Dunmanway killings
Capital punishment in Ireland