What is the conflict of The Sniper?

The conflict in The Sniper arises out of the Irish civil war, where, literally the fight in Ireland was brother against brother. It is difficult to know who the enemy is in a fight of this kind.

In the story, a sniper is perched on a roof, watching for enemy activity in the town below.  He spots an old woman, who appears to be helping the enemy. He shoots at the soldier she spoke to and then shoots her.

Then an enemy sniper fires a shot from a neighboring rooftop and the sniper is hit.  After a long drawn out process the sniper finally fires and hits the enemy sniper, killing the man who falls off the roof. 

When the Sniper, the narrator, ends up shooting his enemy, he goes down from the rooftop to look at the face of the enemy that he killed. When he turns the body over, he discovers that the enemy that he shot is in fact his own brother.