Do you think Ambrose Bierce tries to enlist your sympathies toward either the Union or Confederate side in his short story "An Occurrence at Owl Creek Bridge"? Or, does the story seem more focused on a more general theme about the nature of war?
Bierce, a former officer in the Union army during the Civil War, who spent much of his time in the Kentucky and Tennessee theater of war, wrote many short stories about the war. One of the consistent features of his short stories is a lack of comment about which side was right or wrong. It is correct to say that Bierce was essentially against war but steered clear of discussing the rightness or wrongness of the cause of war.
In "An Occurrence at Owl Creek Bridge," we find no condemnation or support of either North or South. Bierce uses the vehicle of the story to discuss, among other things, the brutality of war, its senselessness, in the context of a psychological thriller with a typically Bierce surprise ending.
Bierce felt that war--no matter the cause--was the ultimate expression of brutality in human nature--but he preferred to make that case indirectly. In "An Occurrence," he depicts a classic case of a non-combatant, Peyton Farquhar, sabotaging a bridge to make life more difficult for the invading Yankees. Because Farquhar was not acting as a uniformed soldier--and therefore entitled to the protections accorded a combatant when caught as a prisoner--Farquhar is treated as a saboteur and a spy. Such men were routinely executed during the war without a trial and often with little or no actual evidence. That is the kind of brutality that Bierce hated passionately, bu the preferred to attack it by letting it speak for itself.
The closest Bierce comes to condemning war is in his description of Farquhar's motives for destroying the bridge:
No service was too humble for him to perform in the aid of the South, no adventure too perilous for him to undertake . . . and without too much qualification assented to , , , the frankly villainous dictum that all is fair in love and war.
Bierce's comment that the concept "all is fair in love and war" is, in the final analysis, "frankly villainous" is the only explicit condemnation Bierce makes about war in the story. He is clearly saying that war is a terrible enterprise, but he's condemning not only war but also those who think "all is fair in love and war," and that includes Farquhar's executioners as well as Farquhar himself.