In 2016 the United Kingdom had a referendum in which most British people voted to leave the European Union.This British Exit from the EU, is called “__1__” for short.The border between Northern Ireland and the Republic of Ireland was first drawn in __2__ by the British, who had ruled over the island for centuries.The large, southern part that became the Republic of Ireland was historically Catholic, identified as Irish, and wanted independence. They were known as __3__But in the North, many people were Protestant, identified more closely as British and wanted to stay in the UK. They were called __4__.Tensions between these two parts become more and more strained and eventually violent.The Nationalists extremist group (IRA) and Unionist extremist group fought each other for more than __5__ years, during this time over 3,600 people were killed and it came to be known as "The __6__"It ended in 1998, with the two parties signing the Good __7__ Agreement.The big problem with the UK leaving the EU is that it could cause trouble between the IRA (nationalists) and the unionists once again. The problem is that the UK needs to put a border somewhere between them and the EU, but cannot decide where.The only viable option left is the fourth option, it's the idea of __8__. Which means Northern Ireland would join Ireland and become one country separate from the UK.This would've been a problem in the past. But even the Unionists are not fans of Brexit and wanted to remain in the EU.The way that both British and Irish cultures broadly have integrated into and participated in the processes of the EU has been on a gradual path of ideoligical __9__ for a generation or so by now.Which means that the UK, especially England, may be losing Northern Ireland and even Scotland due to their differences in opinion. One being, on the whole, pro-EU, and the other not.