What is the message the author is sending in the story "The Sniper"?

The ending of O'Flaherty's short story certainly presents a message which focuses on the cruelty and familial divisiveness of civil wars.  When the sniper discovers that he has killed his own brother, the author clearly shows how Ireland's war with itself pitted brother against brother (much like the American Civil War).  Most critics consider this to be the primary message of the story.

However, the beginning and middle parts of the story also allow the author to illustrate the mind and nature of a warrior. His almost mechanical description of the sniper demonstrate the effects of war and combat on an individual.