In Liam O'Flaherty's short story, "The Sniper," the theme that most strikes me is that in war, there are no winners, regardless of who kills more people or takes more land, etc.
When the Republican sniper kills the driver of the tank and the informant, he perceives success, though the death of these two does not make any difference in the sniper's intent to turn the tide of the war to the benefit of the Republican army.
Then around the corner of a side street came an old woman, her head covered by a tattered shawl. She began to talk to the man in the turret of the car. She was pointing to the roof where the sniper lay. An informer.
The woman is most likely an occupant of the neighborhood who is tired of the fighting and the inability to move safely through the streets. She has no money—as noted by the "tattered shawl."
The sniper kills the driver of the tank.
The turret opened. A man's head and shoulders appeared, looking towards the sniper. The sniper raised his rifle and fired. The head fell heavily on the turret wall. The woman darted toward the side street. The sniper fired again. The woman whirled round and fell with a shriek into the gutter.
The woman's imagined concern over her lack of safety is proven with her death. The armored car (tank) has quickly fled, and the sniper has been hit by a Free Stater sniper on another roof. Not only are there no winners in war, but in this civil war, innocent people—women, children, the elderly—are killed. The woman seems like an enemy to the sniper, but she is simply a woman who wants her life back from war. The sniper sees things only in terms of warfare; there is nothing unfair in his mind in killing the old woman—she's an informant.
We also understand that civil war separates families as seen in the War Between the States in the United States in the 19th Century. The truth of the terrible waste of war and the horrific toll it takes upon a society, and humanity in general, is seen when the sniper turns over the dead man he has killed.
...he felt a sudden curiosity as to the identity of the enemy sniper whom he had killed. He decided that he was a good shot whoever he was. He wondered if he knew him. Perhaps he had been in his won company before the split in the army.
The sniper anticipates it might be a former friend and yet he still does not recoil from looking at the dead man. We know how we feel learning that the man has killed his brother, but we are left to wonder as to his reaction because it seems he has become so desensitized to the death of others in this war that he might not be changed at all—we can never be sure.
There truly are no winners in war.