The military conflict itself, by dominating everything in its time, diminished other issues, made people choose sides in the one contest that was publicly important, forced people onto the side of the Revolution whose interest in independence was not all obvious. Ruling elites seem to have learned through the generations - consciously or not - that war makes them more secure against internal trouble.
The Conscription Act of 1863 provided that the rich could avoid military service: they could pay $300 or buy a substitute. Morgan had escaped military service in the Civil War by paying $300 to a substitute. So did John D. Rockefeller, Andrew Carnagie, Philip Armour, Jay Gould, and James Mellon. Mellon’s father had written to him that "a man may be a patriot without risking his own life or sacrificing his health. There are plenty of lives less valuable." The conscription law of the Confederacy too provided that the rich could avoid service.
The psychology of patriotism, the lure of adventure, the aura of moral crusade created by political leaders, worked effectively to dim class resentments against the rich and powerful, and turn much of the anger against "the enemy." In fact, the military became a place of promise for the poor, who might rise in rank, acquire some money, change their social status.