system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:ELI5:What is the difference between the "IRA" the "Real IRA", the "Provisional IRA" and the "Continuity IRA".
gpt
The Irish Republican Army fought against the British during the Irish War of Independence. The war concluded with a treaty in 1921 that established the Irish Free State, but left Northern Ireland under British rule. Members of the IRA that were against the treaty fought civil war against the Free State, which they lost in 1922, and continued to fight a guerrilla war against Northern Ireland thereafter, keeping the "IRA" name. They viewed themselves as the legitimate organizational successor of the group that had fought for Irish independence originally.

In 1969, the movement split based on ideology. The "Provisional IRA" retained the traditional Catholic/nationalist perspective of Irish independence, while the "Official IRA" were Marxist.  The "Continuity IRA" split off from the Provisional IRA over a dispute about political participation: the Provisional IRA had long supported the concept of absenteeism, which is that Irish nationalists should be elected to the Republic of Ireland's parliament but refuse to participate, as a means of undermining it. In the late '80s, the Provisional IRA wanted to end its support of abstentionism (as part of a path to a less military approach), but the Continuity IRA continued to support it.

The Provisional IRA called a ceasefire in the mid-'90s, which permitted the negotiations that led to the Good Friday Agreement that ultimately saw the end of most attacks in Ireland and a destruction of weapons, as well as the release of IRA prisoners and formal British recognition that the Irish people should have self-determination. But the "Real IRA" split off from the Provisionals opposed the ceasefire and agreement, and continues to advocate for guerrilla war as the path to united Irish independence.

When people say "*the* IRA" in reference to the Troubles, they usually mean the Provisional IRA.