To focus way too deeply on just the ireland bit:

Ireland (the island) is presently separated into Ireland (the country) and Northern Ireland (part of the UK). This was the compromise made in the early 1900s after repeated attempts to throw off British occupation of Ireland, and except for some changes to the governance of Northern Ireland, that split arrangement also survived the Troubles (a period of violent resistance against British occupation of NI by the IRA and other related groups in the 1970s), but the unification of all of Ireland (the island) into one country, free of British rule and interference, remains a strong desire for many Irish people.

Star Trek had an episode where Data referenced the "Irish Unification of 2024" as a case where violence/terrorism was used to effect positive political change. Basically implying that a resumption of "terrorist" activity a-la the Troubles had resulted in finally achieving Irish unification. Link: https://www.youtube.com/watch?v=IbSGp4WIBsQ

It's also popular here in part because Picard disparagingly references a Mao quote before getting several counter-examples thrown in his face by Data