Irish Republican Army (1922–1969)

The split in Sinn Féin and the Irish Republican Army following the signing of the Anglo-Irish Treaty in 1921 led to the emergence of group of Anti-Treatyites, sometimes called the Irregulars, who continued to use the name IRA but who are often called simply the Anti-Treaty IRA.

At the end of the Civil War the Irregulars remaining in the field neither surrendered nor were stood down; rather, they received an order to "dump arms". Many of them were already prisoners of the government forces; many more were arrested after they dumped arms and returned to civilian life. The prisoners were released over the following period, with Eamon De Valera last to leave Kilmainham Gaol in 1924. In 1926, after failing to persuade Sinn Féin to participate in the political institutions of the Free State, De Valera formed a new political party, called Fianna Fáil, and many IRA members left to support him.

From 1926 to 1936, the remainder of the IRA was led by Moss (Maurice) Twomey. The organisation was increasingly influenced by left-wing ideas, and many Communist Party of Ireland members were also members of the IRA during this period. Political initiatives such as Saor Éire in 1931 and the Republican Congress in 1933-1934 were promoted by left-wing IRA members such as George Gilmore, Peadar O'Donnell and Frank Ryan. However, the Republican Congress was ultimately a failure, partly because Twomey and other conservative elements in the IRA leadership opposed it and forced its supporters to leave the organisation. From the debacle of the Republican Congress until it took a leftward turn again in the 1960s, the IRA would be inspired primarily by a conservative, strictly nationalist political outlook.

In 1932 Fianna Fáil under De Valera formed its first government, and republican prisoners were released and the organisation unbanned. Confrontations between the IRA and the Blueshirts were a feature of political life in the Free State in the 1930s. From 1937 on, government repression increased again, and during the Second World War IRA members were interned both north and south of the border. A number of IRA men, including chief of staff Charlie Kerins, were executed by the Irish government during the war.

Elements in the IRA hoped for support from Germany to strike against Britain during the war, and Seán Russell travelled to Germany in 1940 to canvass for arms. He became ill and died on board a German U-boat which was bringing him back to Ireland in August that year.

By the late 1930s at the latest, most Irish people disagreed with the residual Irish Republican Army's claims that it remained the legitimate 'army of the Republic'.

A brief border campaign in the 1950s failed to restore the IRA's fortunes, and in the 1960s it once more came under the influence of left-wing thinkers, especially those such as Desmond Greaves active in the Connolly Association in London. This move to a class-based political outlook and the consequent rejection of any stance that could be seen as sectarian - including the use of IRA arms to defend the beleaguered Catholic communities of Belfast in 1969 - was to be one of the factors in the 1969 split between the official and provisional wings of the republican movement.