https://www.americanantiquarian.org/earlyamericannewsmedia/files/original/2c8a67aff67763b34a6fcd3a9751e24c.jpgThis map, primitive as it is, illustrates the difficulty for the secessionists. They were up against a wired nation. The US Civil War was the second major war involving use of the electrical telegraph for reporting and management. The first was the Crimean War.
While inertia favored the Confederates, they were not going to get the benefit of weeks and months as news of the rebellion crossed an ocean and the response recrossed the ocean. Within hours of Fort Sumter, the US knew of the crisis, and within days, the administration knew whether the state governors of the northern states intended to respond with force.
This map, from 1856, shows the multiple, complex communication networks spread across the main part of the US at that time.