In Liam O'Flaherty's story, The Sniper, the main idea or theme the author is trying to convey is the way war changes not only individual people but the society in which they live. In support of the two sides in the Irish civil war in 1922, two brothers chose differently. As the sniper on the rooftop tries to kill his opponent, he goes through many emotions. He knows he must be off the rooftop before daylight or he will be seen. Through a clever ruse, he kills the other sniper and manages to kill the soldier on the street and the woman who is pointing him out. As the sniper climbs down to street level, he is torn with the thoughts of what this war has done to him who was essentially a student which is to make him a killer. He no longer feels the same drive to kill the man lying before him. When the sniper turns over the man he has shot, he discovers that he has killed his own brother. His emotions have gone from excitement to kill the sniper and survive, to regret what the war has done to him, regret over his brother, and back to the excitement of rejoining his fighting group to continue his part in the war effort.