Irish politician, journalist, and historian. O'Brien entered the Department of External Affairs in 1944, and was a member of the Irish delegation to the United Nations 1956–60. In 1969 he became a Labour Party minister, representing Dublin Northeast in the Irish parliament. He had a controversial career as minister for posts and telegraphs (1973–77), when he introduced legislation prohibiting the appearance of representatives of Sinn Fein on Irish radio and television, and as Labour Party spokesperson on Northern Ireland. In 1977 he was appointed editor of The Observer.
In 1961 O'Brien was the United Nations secretary general Dag Hammarskjöld's representative in Katanga, Congo; his book, To Katanga and Back (1962), describes the crisis in Congo following that country's independence. He was vice-chancellor of Ghana University 1962–64 and Schweitzer professor of the humanities at New York University 1965–69. His other publications include Maria Cross (1952), a study of French Catholic writers, Parnell and His Party (1957), Writers and Politics (1965), Camus (1969), A Concise History of Ireland (1972), States of Ireland (1972), and his study of Edmund Burke: The Great Melody (1999).
Although O'Brien participated as a civil servant in early anti-partition campaigns, his strong political opposition to the IRA led him increasingly to criticize traditional Irish nationalism and irredentism, particularly the variety espoused by Fianna Fáil. His views always generated fierce controversy in the Republic, and eventually he left the Irish Labour Party and joined the UK Unionist Party.
O'Brien, Conor Cruise