Seán Gerard Cronin, journalist and former Irish Army officer and twice Chief of Staff of the Irish Republican Army (IRA), dies on March 9, 2011, in Baltimore, Maryland.

Cronin is born on August 29, 1922, in Dublin, the only son among three children of Con Cronin, a member of the IRA, and his wife Kate. After his father’s death, his mother works as a cook in a boarding school while the children are brought up by relatives in Ballinskelligs in the County Kerry Gaeltacht. Educated locally, he is deeply influenced by his Gaeltacht childhood; his later writings often refer to the hypocrisy of a state that romanticises the Gaeltacht while neglecting its social problems.

During World War II, Cronin’s sisters emigrate to England to train as nurses while he works as a labourer for Kerry County Council. In December 1941, he joins the Irish Army and is selected in 1943 for an officers’ training course, on which he forms a lifelong friendship with the future theatre director Alan Simpson. He is commissioned and remains in the army until 1948.

Shortly thereafter Cronin emigrates to New York City, where he finds work as a journalist writing for The Advocate, an Irish American newspaper. He is strongly influenced by interviewing 1916 veterans for The Advocate and by contact with left-wing Irish American associates of Michael Quill, who played leading roles in the foundation of the Transport Workers Union of America. He becomes active in the semi-secret separatist organisation Clan na Gael, and in autumn 1955 returns to Ireland with the aim of helping the IRA to prepare for another military campaign.

Cronin begins work as a sub-editor with the Evening Press and also contributes summaries of world affairs to The Irish Times.

Cronin establishes contact with the IRA, and his military experience leads to his rapid assignment to GHQ staff. He is initially placed in charge of training and instruction, composing a manual on guerrilla warfare and twelve lectures on battlefield training. He teaches new military techniques and new recruits, such as the future IRA Chief of Staff Ruairí Ó Brádaigh, find him deeply impressive.

Cronin becomes a leading advocate of an early IRA campaign against Northern Ireland and becomes the chief strategist for Operation Harvest, a campaign which sees the carrying out of a range of military operations from direct attacks on security installations to disruptive actions against infrastructure. He is arrested on January 8, 1957, near the border in County Cavan. He is imprisoned several times over the course of the campaign (1956–1962).

Most of the IRA and Sinn Féin leadership are interned by the Dublin government on July 6, 1957. Cronin, one of the few to escape, becomes IRA Chief of Staff. He also acts for a time as editor of the movement’s newspaper, United Irishman. He tries to secure weapons from various sources, leading an unsuccessful raid on a British Army base at Blandford Camp in Dorset on February 16, 1958, and through contacts with Spanish republican exiles in Paris. The Irish American community remains the IRA’s main source of external support.

Cronin is arrested on September 30, 1958, and interned, causing considerable disarray, as he had been running much of the campaign single-handed. When the internees are released in March 1959, he resumes his position as Chief of Staff after a factional dispute causes the resignations of Tomás Óg Mac Curtain and the former Chief of Staff Tony Magan. He continues to argue that a sustained guerrilla campaign might yet succeed, but in June 1960 is again arrested and imprisoned for six months.

In November 1960, the Irish Freedom Committee (IFC), a Clan na Gael splinter group, accuses Cronin of being a communist and a “Free State agent,” supposedly implicated in the 1944 execution of Charlie Kerins. The IRA supports Cronin, but he nevertheless decides to resign successively as Chief of Staff, as a member of the Army Council, and as an IRA volunteer, on the grounds that his presence endangers the American support necessary for the continuance of the campaign. He then secures a job as a journalist on the Irish Independent. He withdraws his resignation in November 1961 after the Irish government reinstates military tribunals to try suspected IRA men. He is subsequently sentenced to six months’ imprisonment by a military tribunal and is in prison when the border campaign ends on February 26, 1962. Released on amnesty on April 19, 1962, he finally resigns from the IRA the next day.

By February 1966, Cronin has returned to the United States, where he resides for the remainder of his life, with regular visits to Ireland. He works as a journalist on the Newark Evening News and the Dow Jones News Service and is the U.S. correspondent of The Irish Times from 1967 to 1991, becoming that paper’s first Washington, D.C. correspondent.

In the 1970s Cronin takes a degree at New York University, then teaches and studies for a doctorate at The New School for Social Research in New York under Hans Morgenthau. His dissertation forms the basis for his magnum opus, Irish nationalism: its roots and ideology (1980). Although limited by its colonial model and socialist-republican intellectual framework, this historically oriented account draws on his extensive research and personal contacts to some effect.

Cronin is the author of a dozen books and pamphlets, including a biography of republican Frank Ryan, Washington’s Irish Policy 1916-1986: independence, partition, neutrality (1987), an authoritative account of Irish-US relations, Our Own Red Blood: The Story of the 1916 Rising (1966), and a number of works on guerrilla strategy, including an early Sinn Féin pamphlet Resistance under the pseudonym of J. McGarrity.

After the death of his first wife in 1974, Cronin marries Reva Rubinstein, a toxicologist. In 1980 they move to Washington, D.C. He has no children by either marriage, though his second wife brings him a stepson. After several years of illness, he dies in Baltimore, Maryland, on March 9, 2011. He is survived by his second wife, Reva Rubenstein Cronin.