Partition of Ireland
Beginning on 21 January 1919 with the Soloheadbeg ambush, through the Irish War of Independence, Irish republicans attempted to bring about the secession of Ireland from the United Kingdom of Great Britain and Ireland. Meanwhile, Irish unionistsmost of whom lived in the northeast of the islandwere just as determined to maintain the Union. The British Government, committed to implementing Home Rule, set up a cabinet committee under the chairmanship of southern unionist Walter Long. The Long Committee recommended the establishment of two devolved administrations, dividing the island into two territories: Northern Ireland and Southern Ireland. This was implemented as the Government of Ireland Act 1920. The act entered into force as a "" on 3 May 1921 and provided that Northern Ireland would consist of the six northeastern counties, while the remainder of the island would form Southern Ireland. It was intended that each jurisdiction would be granted home rule but remain within the United Kingdom. The government of Southern Ireland never functioned: the war for independence continued until the two sides agreed a truce in July 1921, ending with the Anglo-Irish Treaty on 6 December 1921.
Irish republicanism
In 1948, Fianna Fáil went out of office for the first time in sixteen years. John A. Costello, leader of the coalition government, announced his intention to declare Ireland a republic. The Republic of Ireland Act 1948, which "described" the state as the Republic of Ireland (without changing its name), led the British government to pass the Ireland Act 1949, which declared that Northern Ireland would continue as part of the United Kingdom unless the Parliament of Northern Ireland consented to leave; and Ireland ceased to be a member of the Commonwealth. As a result of this—and also because continuing struggle against the Dublin government was futile—the republican movement took the decision to focus on Northern Ireland from then on. The decision was announced by the IRA in its Easter statement of 1949.