Of course, in the 1860s, long distance could have
I had both, long and field distances in mind. Yes, Especially field telephones ( primitive WW1 style) would require some technological advancement. Iam not sure how realistic long distances could be for the 1860es. It would be interesting to see, how generals communicate with their staff, or Lincoln giving orders to McClellan through telephone. Maybe the hole political debate regarding the abolution of slavery could have a new dimension, with telephones installed in Lincolns office.
Best,
Of course, in the 1860s, "long distance"
could have been from the White House to the War Department, much less Washington DC to Alexandria, Virginia.
More seriously, the Civil War was the first conflict where the national command authority (in the US) was in what amounted to real-time and close to all-weather communications with the theater commanders' headquarters (not necessarily the same thing as the commander himself, of course), although that ended if Grant or Sherman or whoever went aboard a steamboat, mounted their horse for an inspection or reconnaissance, or what have you...
But it definitely allowed the US to get well inside the rebels' OODA loop, consult and create effective grand strategies, provide reinforcements in a timely manner at the theater level, and - probably most of all - kept the railroads and the supply chains they served operating smoothly.
None of which gets much attention compared to the gallant crusaders' uniforms and the important question of whether if one is more dead from a .54, .577, or .58 caliber bullet in the gut, but what have you.
It's an interesting question. Early adopters have to deal with technical immaturity, but they also reap the benefits of an edge if the technology is robust enough to function, even in its early stages - definitely a two-edged sword.
Best,