In January 1919, Sinn Féin MPs refuse to recognise the Parliament of the United Kingdom and instead assembles in the Mansion House, Dublin as a revolutionary parliament called Dáil Éireann. McCan never sits in Dáil Éireann, dying in prison on March 6, 1919, during the Spanish flu pandemic. On March 9, 1919, he is buried in Dualla, Cashel, County Tipperary.
No by-election is called to replace him in the UK constituency. After April 1, 1922, the Irish Free State (Agreement) Act 1922 prohibits any by-election, and the constituency is abolished when parliament is dissolved on October 26, 1922, for the general election on November 15.
The First Dáil also considers how to fill the vacancy. A select committee in April recommends that the local Sinn Féin organisation which nominated him should nominate his replacement. A June proposal to postpone action, either for six months or until a Westminster by-election is held, is referred to another committee, which recommends that “in view of the circumstances which occasioned the vacancy, it was due to the memory of the late Pierce McCann that his place should not be filled at present.”
On April 10, 1919, Cathal Brugha tells the First Dáil: “Before I formally move the motion, as I have mentioned the name of Pierce McCan, I would ask the Members of the Dáil to stand up as a mark of our respect to the first man of our body to die for Ireland, and of our sympathy with his relatives. We are sure that their sorrow is lightened by the fact that his death was for the cause for which he would have lived, and that his memory will ever be cherished in the hearts of the comrades who knew him, and will be honoured by succeeding generations of his countrymen with that of the other martyrs of our holy cause.” The McCan Barracks in Templemore, County Tipperary, is named after him.
Together with his brother Norman, Leslie’s early education begins at home where a German governess, Clara Woelke, is their first teacher. As children the brothers have more contact with servants than they have with their parents. His own daughter, Anita, says, “In my parents’ view schools performed the same functions that kennels did for dogs. They were places where pets could be conveniently deposited while their owners travelled.”
Leslie is educated at Ludgrove School, then Eton College and King’s College, Cambridge. While at Cambridge University he becomes a Roman Catholic and a supporter of Irish Home Rule. He adopts an anglicised Irish variant of his name (“Shane”). Not overly impressed by Eton, as a lower boy he and his roommates occupy “an old, battered warren betwixt the chapel cemetery and Wise’s horse yard … [T]he food was wretched and tasteless … As for thrashings which tyrannised rather than disciplined our house, they were excessive. Bullying was endemic and Irish boys were ridiculed, especially on St Patrick’s Day.”
Leslie refuses to send his own sons to Eton. They are educated at Roman Catholic Benedictine schools: Jack at Downside School and Desmond at Ampleforth College.
During the war Leslie is in a British Ambulance Corps, until invalided out. He is then sent to Washington, D.C. to help the British Ambassador, Sir Cecil Spring Rice, soften Irish American hostility toward England and obtain American intervention in the war in the aftermath of the 1916 Easter Rising in Dublin and the execution of its leaders. But he also looks to Ireland for inspiration when writing and edits a literary magazine that contains much Irish verse. He becomes a supporter of the ideals of Irish nationalism, although not physical force republicanism.
In the 1918 United Kingdom general election in Ireland, the Irish Parliamentary Party loses massively to Sinn Féin, putting an end to Leslie’s political career, but as the first cousin of Winston Churchill he remains a primary witness to much that is said and done outside the official record during the negotiation of the Anglo-Irish Treaty of 1921. Disappointed, he feels unwanted in Ireland and abandoned by the British. Like many members of the landed gentry from the 1880s who were obliged to turn to other occupations, he can no longer rely on income from landholdings.
Leslie writes extensively, in a wide range of styles, in verse, prose, and polemic, over several decades. His writings include The End of a Chapter (1916), while hospitalised during World War I, The Oppidan (1922), a roman à clef about his life and contemporaries at Eton, an edition of the Letters of Herbert Cardinal Vaughan to Lady Herbert of Lea (1942), and a biography Mrs. Fitzherbert: a life chiefly from unpublished sources (1939), together with an edition of her letters (with Maria Anne Fitzherbert), The letters of Mrs. Fitzherbert and connected papers; being the second volume of the life of Mrs. Fitzherbert (1944). He also writes Mark Sykes: His Life and Letters (1923), a biography of the English traveler, Conservative Party politician and diplomatic advisor. He advises budding novelist Scott Fitzgerald on the title of his first novel, they share correspondence with the future Mnsg. William A. Hemmick, who is Fitzgerald’s teacher at the Newman School.
A passionate advocate of reforestation, Leslie finds the business of running an estate uncreative and boring, and transfers the estate entailed to him to his eldest son, John Norman Leslie, who succeeds as the 4th Baronet. He transfers St. Patrick’s Purgatory on Lough Derg to the Roman Catholic Bishop of Clogher, Eugene O’Callaghan.
The wealth of the Leslies wanes by the 1930s following the Wall Street crash of 1929 and a farm that is loss making. In his unpublished memoirs, Leslie writes “a gentleman’s standing in his world was signalled by his list of clubs and it was worth paying hundreds of pounds in subs.” They continue to maintain their lifestyle, involving attendance at the London season and the entertainment of distinguished visitors, including Anthony Eden at Glaslough. At the outbreak of World War II in 1939 he joins the Home Guard. He spends the remainder of his life between Glaslough and London.
Leslie’s first wife, Marjorie, dies on February 8, 1951. On May 30, 1958, at the Catholic Church of St. Peter & Edward, Westminster, he marries Iris Carola Frazer, who is the daughter of Charles Miskin Laing and Etheldreda Janet Laing.
An active member of parliament, O’Conor is an effective though not an eloquent speaker and a leading exponent of Roman Catholic opinion. He frequently speaks on Irish education and land tenure. He criticises unfavourably the Queen’s Colleges established in 1845 and the model schools, and advocates separate education for Roman Catholics. In 1867 he introduces a measure to extend the Industrial Schools Act to Ireland, which becomes law the following year.
O’Conor opposes William Ewart Gladstone‘s Irish University Bill of 1873, and in May 1879 brings forward a measure, which has the support of almost every section of Irish political opinion, for the creation of a new examining university, St. Patrick’s, with power to make grants based on the results of examination to students of denominational colleges affiliated to it. This is withdrawn on July 23 on the announcement of the University Education (Ireland) Act 1879 creating the Royal University of Ireland.
O’Conor steadily lurges a reform of the Irish land laws. On social and industrial questions he also speaks with authority. From 1872 onwards he professes his adherence to home rule and supports Isaac Butt in his motion for inquiry into the parliamentary relations of Great Britain and Ireland in 1874. He also acts with the Irish leader in his endeavours to mitigate the severity of coercive legislation, though declaring himself not in all circumstances opposed to exceptional laws.
Following his parliamentary career in 1880, O’Conor is a member of the Registration of Deeds Commission of 1880, and takes an active part in the Bessborough land commission of the same year. He is a member of both the parliamentary committee of 1885 and the royal commission of 1894 on the financial relations between Great Britain and Ireland, and becomes chairman of the commission on the death of Hugh Culling Eardley Childers in 1896. He is also active in local government, presiding over parliamentary committees on Irish grand jury laws and land valuation in 1868 and 1869, and being elected to the first county council of Roscommon in 1898. He is Lord-Lieutenant of the county from 1888 until his death.
O’Conor is much interested in antiquarian studies. He serves for many years as president of the Antiquarian Society of Ireland, as well as of the Royal Irish Academy. He is president of the Irish Language Society, and procures the insertion of Irish language into the curriculum of the intermediate education board.
O’Conor dies at Clonalis House, Castlerea, County Roscommon, on June 30, 1906, and is buried in the new cemetery, Castlerea.