If the Army of Northern Va were to have captured DC, it would have been considered a tactical victory, not a strategic victory. The South wasn’t interested in taking and holding Northern territory. The whole point of secession was the opposite of that. I feel like I am talking to someone with less than a full deck when I post to you. Kind of a creepy feeling I get.
Sorry, southern armies invaded several states and territories. Arizona, Missouri, Kentucky, Vermont(!) Pennsylvania, and Maryland.
That indicates that they didn’t want to be let alone. In like manner, their attacks on US forts indicates that they wanted a war. South Carolina, too small to be a country and too large to be an asylum, needed a war to bring in Virginia.
They wanted a war. They got it. They lost it. The problem was the US didn’t hang enough traitors.