McCorley was a member of the Belfast Brigade of the Irish Republican Army during the Irish War of Independence, 1919–1922. He was commandant of the Brigade's first battalion. In June 1920, he was involved in an attack on a Royal Irish Constabulary Police barracks at Crossgar, county Down. On Sunday August 22, 1920 in Lisburn, McCorley was involved in the assassination of DI Oswald Swanzy, Royal Irish Constabulary who was held responsible by Michael Collins for the assassination of Tomas McCurtain, Lord Mayor of Cork. McCorley was noted for his militancy, as he was in favour of armed attacks on British forces in Belfast. The Brigade's leaders, by contrast, in particular, Joe McKelvey, were wary of sanctioning attacks for fear of loyalist reprisals on republicans and the Catholic population in general. In addition, McCorley was in favour of conducting an armed defence of Catholic areas, whereas McKelvey did not want the IRA to get involved in what he considered to be sectarian violence. McCorley wrote later that in the end, 'the issue settled itself within a very short space of time, when the Orange mob was given uniforms, paid for by the British, and called the Ulster Special Constabulary'. The role of the USC, a temporary police force raised for counter-insurgency purposes, in the conflict is still debated, but republicans maintain that the organisation was responsible for the indiscriminate killings of Catholics and nationalists.
On 26 January 1921, McCorley, was involved in the fatal shooting of three Auxiliary Division officers in their beds in the Railway View hotel in central Belfast. Shortly afterwards, McCorley and another IRA man, Seamus Woods, organised an Active Service Unit within the first battalion of the Belfast Brigade, with the intention of carrying out attacks, with or without the approval of the Brigade leadership. The unit consisted of 32 men. McCorley later wrote, 'I issued a general order that, where reprisal gangs were cornered, no prisoners were to be taken'. In March 1921, McCorley personally led the ASU in the killing of three Black and Tans in Victoria street in central Belfast. He was responsible for the deaths of two more Auxiliaries in Donegall Place in April. In reprisal for these shootings, members of the Royal Irish Constabulary assassinated two republican activists, the Duffin brothers in Clonard Gardens in west Belfast. Thereafter, there was what historian Robert Lynch has described as a, 'savage underground war' between McCorley's ASU and RIC personnel based in Springfield Road barracks and led by an Inspector Ferris. Ferris himself was among the casualties, being shot in the chest and neck, but surviving. In addition, McCorley's men bombed and burned a number of businesses including several cinemas and a Reform Club. In May 1921, however, 13 of McCorley's best men were arrested when surrounded by British troops during an operation in county Cavan. They were held in Crumlin Road jail and sentenced to death. On 3 June, McCorley organised an attack on Crumlin Road jail in an attempt to rescue the IRA men held there before they were executed. The operation was not a success, however the condemned men were reprieved after a truce was agreed between the IRA and British forces in July 1921.
Belfast Brigade leader
In April 1922, McCorley became leader of the IRA Belfast Brigade after Joe McKelvey went south to Dublin to join other IRA members who were against the Anglo-Irish Treaty. McCorley for his part, supported the Treaty, despite the fact that it provided for the partition of Ireland and the continued British rule in Northern Ireland. The reason for this was that Michael Collins and Eoin O'Duffy had assured him that this was only a tactical move and indeed, Collins sent men, money and weapons to the IRA in the North throughout 1922. However, McCorley's command saw the collapse of the Belfast IRA. In May 1922, the IRA launched an offensive with attacks all across Northern Ireland. In Belfast, McCorley carried out an assault on Musgrave Street RIC barracks. He also conducted an arson campaign on businesses in Belfast. His men also carried out a number of assassinations, including that of Unionist MP William Twaddell, which caused the internment of over 200 Belfast IRA men.
To escape from the subsequent repression, McCorley and over 900 Northern IRA men fled south, to the Irish Free State, where they were housed in the Curragh. McCorley was put in command of these men. In June 1922, the Irish Civil War broke out between Pro and Anti-Treaty elements of the IRA. McCorley took the side of the Free State and Michael Collins. After Michael Collins was killed in August 1922, McCorley's men were stood down. About 300 of them joined the National Army and were sent to County Kerry to put down anti-Treaty guerrillas there. In the Spring of 1923, McCorley, bitterly disillusioned by the brutal counter-insurgency against fellow republicans, resigned his command. He recalled he was, 'fed up', with the civil war. He later asserted that he 'hated the Treaty' and only supported it because it allowed Ireland to have its own armed forces. In 1936 he was instrumental in the establishment of the All-Ireland Old IRA Men's Organisation, serving as Vice-President with President Liam Deasy and Secretary George Lennon.
Coras na Poblachta
In the 1940s, McCorley was a founding member of Córas na Poblachta, a political party which aspired to a United Ireland and economic independence from Britain.
