Brexit and the Irish Civil War

The pro and anti treaty debates and subsequent civil war in Ireland redefined the whole landscape of Irish politics for at least 70 years (in some ways they are still a defining factor today). The way the recent referendum has split our country into two opposing camps around a single issue has, in a small (and thankfully less bloody) way, helped me (as someone who is interested in early 20th Century Irish history) to understand how such a lasting re-entrenchment could have occured.