Great wars have long-range effects on their participants, especially the combatants who survive and then must re-establish themselves in a post-war society. In the often comparatively brief periods of service, a soldier's future may be greatly influenced by the harsh experiences of combat. Great wars also may greatly affect the path of societies engaged in such wars. And long-range effects of war also may be sensed in relation to the unfulfilled hopes and dreams of those combatants who do not survive.
It is easier—although not necessarily easy—to measure the effects on those who do survive, as their subsequent lives may provide testimony to their war experiences, directly or indirectly. For those who do not survive, it can only be surmised as to what they might have done after the war, had they been given the chance.
David Whitney and his brothers-in-law can be viewed as examples of war veterans who went on to contribute greatly to the surviving society, in part in the way they perservered in their pioneering push westward despite many hardships and obstacles—which must have had similarities to some of the events of war they had experienced—and in part in local leadership roles they assumed—which must have drawn on their leadership experiences in war.
In the case of David's brother who served in but did not survive the Civil War, the few things known about his brief life before the war, combined with some things he did and said during the war, allow a guess—but only a guess—at what Alonzo Whitney might have done had he survived.