Donal Conor David Dermot Donat Cruise O'Brien (3 November 1917 – 18 December 2008), often nicknamed "The Cruiser", was an Irish diplomat, politician, writer, historian and academic, who served as Minister for Posts and Telegraphs from 1973 to 1977, a Senator for Dublin University from 1977 to 1979, a Teachta Dála (TD) for the Dublin North-East constituency from 1969 to 1977, and a Member of the European Parliament (MEP) from January 1973 to March 1973.

His opinion of Britain's role in Ireland subsequent to the partition of the island and the independence of the Free State in 1921 changed during the 1970s, in response to the outbreak of The Troubles. He now saw opposing nationalist and unionist traditions as irreconcilable, and switched from a nationalist to a unionist view of Irish politics and history, and from opposition to support for partition. Cruise O'Brien's outlook was radical and seldom orthodox. He summarised his position as intending "to administer an electric shock to the Irish psyche".

Internationally, though a long-standing member of the Irish Anti-Apartheid Movement, he opposed in person the African National Congress's academic boycott of the apartheid regime in South Africa. Views that he espoused during and after the 1970s contrasted with those he articulated during the 1950s and 1960s.

During his 1945–1961 career as a civil servant, Cruise O'Brien promoted the government's anti-partition campaign. In the 1960s he was associated with the 'New Left' and opposition to US military involvement in Vietnam. At the 1969 general election he was elected to Dáil Éireann as a Labour Party TD for Dublin North-East. He served as Minister for Posts and Telegraphs, with responsibility for broadcasting, between 1973 and 1977 in a coalition government. During those years he was also the Labour Party's Northern Ireland spokesman. Cruise O'Brien was later known primarily as an author and as an Irish Independent and Sunday Independent columnist.

Early life Conor Cruise O'Brien was born at 44 Leinster Road, Rathmines, Dublin, to Francis ("Frank") Cruise O'Brien and the former Kathleen Sheehy. Frank was a journalist with the Freeman's Journal and Irish Independent newspapers, and had edited an essay written 50 years earlier by William Lecky concerning the influence of the clergy on Irish politics.William Lecky, Clerical Influences: An essay on Irish sectarianism and English Government, edited with an introduction by W.E.G. Lloyd and F. Cruise O'Brien, Maunsel and Company, Dublin, 1911 (originally published as a chapter in The Leaders of Public Opinion in Ireland (1861)) Kathleen was a teacher of the Irish language. She was the daughter of David Sheehy, a member of the Irish Parliamentary Party and organiser of the Irish National Land League. She had three sisters, Hanna, Margaret and Mary. Hanna's husband, the well-known pacifist and supporter of women's suffrage Francis Sheehy-Skeffington, was executed by firing squad on the orders of Captain J.C Bowen Colthurst during the 1916 Easter Rising. Soon afterwards Mary's husband, Tom Kettle, an officer of the Royal Dublin Fusiliers in the First World War, was killed during the Battle of the Somme. These women, Hanna and Kathleen in particular, were a major influence on Cruise O'Brien's upbringing, alongside Hanna's son, Owen Sheehy-Skeffington.

Cruise O'Brien's father died in 1927. He wanted Conor educated, like Conor's cousin Owen, in Sandford Park School that had a predominantly Protestant ethos, a wish Kathleen honoured.Conor Cruise O'Brien – Obituary by Brian Fallon , The Guardian, London, 19 December 2008 despite objections from Catholic clergy. Cruise O'Brien subsequently attended Trinity College Dublin, which played the British national anthem until 1939. While others stood, he and Sheehy-Skeffington sat in protest on such occasions. Cruise O'Brien was elected a scholar in Modern Languages at Trinity in 1937 and was editor of Trinity's weekly, TCD: A College Miscellany.

His first wife, Christine Foster, from a Belfast Presbyterian family, was, like her father, a member of the Gaelic League. Her parents, Alexander (Alec) Roulston Foster and Anne (Annie) Lynd, were, in Cruise O'Brien's description, "Home Rulers; a very advanced position for any Protestants in the period". Alec Foster was at the time headmaster of Belfast Royal Academy; he was later a founding member of the Wolfe Tone Society, and was a strong supporter of the Irish Anti-Apartheid Movement. He was a former Ulster, Ireland and British & Irish Lions rugby player, having captained Ireland three times between 1912 and 1914. Cruise O'Brien and Christine Foster were married in a registry office in 1939. The couple had three children: Donal, Fedelma, and Kathleen (Kate), who died in 1998. The marriage ended in divorce after 20 years.

In 1962, Cruise O'Brien married the Irish-language writer and poet Máire Mhac an tSaoi in a Roman Catholic church. Cruise O'Brien's divorce, though contrary to Roman Catholic teaching, was not an issue because that church did not recognise the validity of his 1939 civil wedding. He referred to this action, which in effect formally de-recognised the legitimacy of his former wife and their children, as "hypocritical ... and otherwise distasteful, but I took it, as preferable to the alternatives". Mac an tSaoi was five years his junior, and the daughter of Seán MacEntee, who was Tánaiste (deputy prime minister) at the time. The couple subsequently adopted two children of Irish-African parentage, a son (Patrick) and a daughter (Margaret).

Department of External Affairs Cruise O'Brien's university education led to a career in the public service, most notably in the Department of External Affairs. He achieved distinction as managing director of the state-run Irish News Agency and later as part of the fledgling Irish delegation to the United Nations. He later claimed he was something of an anomalous iconoclast in post-1922 Irish politics, particularly in the context of Fianna Fáil governments under Éamon de Valera.

Cruise O'Brien wrote that the Secretary of the department, Joseph P. Walshe, might well have considered that Cruise O'Brien was "no fit person to be a member of Catholic Ireland's Department of External Affairs". Cruise O'Brien attributed his appointment "to a decision taken at a higher level. Under God, there was only one higher level. This consisted of Eamon de Valera, then Minister for External Affairs as well as Taoiseach." Cruise O'Brien speculated that de Valera's Catholicism may have been conditioned by his excommunication during the Civil War of 1922/3, that he may have felt that Walshe had been too close to the previous government, and that he may have been conscious of the nationalist credentials of the Sheehy family, notably Cruise O'Brien's great-uncle, Father Eugene Sheehy, who had been parish priest of Bruree during de Valera's formative years. De Valera later wrote of Father Sheehy, "" (It was he who taught me patriotism).

Cruise O'Brien wrote of his entry into the public service: "The time when I joined the Department of Finance was the first time, since my First Communion, that I found myself in a working environment which was mainly – indeed almost entirely – Catholic". As he admitted, his non-belief did not impede his career, which ended at ambassadorial level. He observed,

In the Department of External Affairs, during the 1948–1951 inter-party government, he served under Seán MacBride, son of John MacBride and Maud Gonne, republican and former IRA Chief of Staff. Cruise O'Brien was particularly vocal in opposition to partition during the 1940s and 1950s, as part of his official duties.

Secondment in Congo He came to prominence in 1961, after his secondment from Ireland's UN delegation as a special representative to Dag Hammarskjöld, Secretary General of the United Nations, in the Katanga region of the newly independent Congo (now the Democratic Republic of the Congo). Cruise O'Brien accused a combination of British, French and white Rhodesian elements of attempting to partition off Katanga as a pro-Western client state. He used military force to oppose a combination of western mercenaries and Katangan forces.

Cruise O'Brien arrived in Élisabethville (modern Lubumbashi) on 14 June 1961, making him the UN's point man for dealing with Moïse Tshombe, the leader of the self-proclaimed independent État du Katanga. The Kasaï Baluba people who formed the majority of the people in northern Katanga were solid supporters of a united Congo, and were the subjects of a ruthless campaign of repression waged by the white mercenaries hired by Tshombe, together with the Katangese gendarmerie. The UN refugee camps were soon overcrowded with thousands of Kasai Baluba people who fled into the refugee camps for their safety. From the viewpoint of O'Brien and other UN personnel, the sooner the crisis was ended, the sooner the refugees could go home. On 28 August 1961, Operation Rum Punch was launched to remove the mercenaries from Katanga as the first step towards reintegrating Katanga into the Congo. On 11 September, Mahmoud Khiary, the chief of the UN mission, gave O'Brien orders to arrest several leading figures within the Etat du Katanga. On 13 September 1961, Operation Morthor was launched, which led Cruise O'Brien to assert prematurely at a press conference that the secession of Katanga was at an end. Tshombe was ordered to be arrested, but he was able to escape via the British consul in Élisabethville to the British colony of Northern Rhodesia (modern Zambia) from whence he returned to Katanga.

Siege of Jadotville

In September 1961, a company of 155 Irish UN troops ("A" Company, 35th Battalion, Irish Army), was surrounded by a force of heavily armed Gendarmerie and mercenaries outnumbering them 20-to-one in Jadotville. The Irish soldiers, many of them still in their teens, were lightly armed, short of ammunition and supplies, and unprepared for the situation. They had been sent to the newly independent Republic of Congo on what was supposed to be a peacekeeping mission but were ordered to the offensive by the UN's most senior diplomat on the ground, Cruise O'Brien, acting on the instructions of the Secretary General, who wanted the Katanga problem solved before the upcoming United Nations General Assembly, as his career was on the line.

The Irish troops held out for six days before they ran out of bullets and drinking water. When water finally reached them, it came in old petrol cans that had not been cleaned, making it undrinkable. The troops inflicted heavy casualties on the enemy force but suffered no fatalities themselves. After their surrender, they spent just over one month in captivity unsure of their fate, and when they arrived back in Ireland, were dismayed and deeply hurt to learn that the UN and their own government were anxious to sweep the episode under the carpet to protect the reputation and to conceal the failures of the UN in preparing for combat and liberating Company A.

Cruise O'Brien wrote immediately about his experiences in The Observer of London and in The New York Times on 10 and 17 December 1961. Armed with the archive material, one expert concluded Hammarskjöld "knew in advance that the UN was about to take action in Katanga and he authorised that action".CONGO 1961, akajava films, broadcast on TG4, September 2012 This is contradicted in a 2022 book on the Congo crisis by historian Wilhelm Agrell.Wilhelm Agrell, Kongokrisen, Historiska Media, 2022, ISBN 9789177897194

Dismissal Faced with the failure of Operation Morthor, Hammarskjöld was on his way to Ndola to meet Tshombe to discuss a ceasefire, but was killed when his airplane crashed during the journey. Cruise O'Brien wrote: "in Élisabethville I do not think there was anyone who believed that his death was an accident".