>If the Army of the Potomac had never crossed the Potomac in 1861 then there would not have been a war. The South wasn’t eager to invade a country with 2.5x the population. Besides the whole point of secession it to end a political relationship not to turn around and occupy them.
Exactly. Which is why it wasn’t a civil war. A Civil war involves sides trying to take over the central government. This was a war of secession exactly like the one the 13 colonies fought against Great Britan, admittedly for a less than noble cause.
It is worth remembering that one of the causes for independence that the slave states cited in the Declaration of Independence was that Britain was interfering with slavery in the colonies.
Let's not pull any punches. The slave states were: New York. New Jersey. New Hampshire. Connecticut. Pennsylvania. Massachusetts. Rhode Island. Delaware. Maryland.
Also Virginia, North and South Carolina, and Georgia.