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.
Partition of Ireland
In May 1949 the Taoiseach John A. Costello introduced a motion in the Dáil strongly against the terms of the UK's "Ireland Act 1949" that confirmed partition for as long as a majority of the electorate in Northern Ireland wanted it, styled in Dublin as the "Unionist Veto". This was a change from his position supporting the Boundary Commission back in 1925, when he was a legal adviser to the Irish government. A possible cause was that his coalition government was supported by the strongly republican Clann na Poblachta. From this point on all the political parties in the Republic were formally in favour of ending partition regardless of the opinion of the electorate in Northern Ireland.