The fundamental issue here is that (southern) Ireland wishes to to have control over the Northern Ireland, and for years this has been part of the Irish constitution.
On the other hand the majority in Northern Ireland (Protestants) do not trust the south, and believe they would loose their identity & rights.
It's easy to find out what people in the North think - hold a referendum and see how they vote. Of course, if you are in favour of forcing sovereign states (which Northern Island is) to agree to being ruled by what they regard as a hostile power, then the solution is easy.
Now that the IRA has mainly ceased its 'military' operations - i.e. killing soldiers & civillians, there is a good chance that over time, a sensible compromise can be reached.
In the past a lot of people in the US have been responsible for prolonging this conflict by funding the IRA 'military' operations via NORAID. Something which gave great offense to many in Northern Ireland and the rest of the UK. Our closest ally sending money to enable terrorists (which is what this part of the IRA are) to buy explosives to kill people.
But recently, things seem to have changed for the better, with the US taking a less partisan approach, and trying to encourage a dialogue between both sides.
