(Sigh!)
I wish you could be made to understand, William, that a nearly 16,000 man army, primarily deployed to patrol and ride herd on Indians, 2/3rds deployed West of the Mississippi, had very little impact on the war that was fought primarily of mobs of volunteers, on both sides.
Advantage? How did all those forts, arsenals, ships, mints, and shipyards fall to those rebel forces before Ft. Sumter? I'll give you one hint. All those US Army forces were OUTNUMBERED by the Confederates who took them.
Sincerely,
Unionblue