OK so what about Fort Bragg? Or say Parris Island, military training bases have lots of troops ... So what if North Carolina wants to leave the Union? Same thing all over again?
The short answer is I dunno. Fort Bragg is a tough one.
North Carolina has about 9 million people so theoretically they could assemble a large enough force to take Fort Bragg directly if they made such a silly decision.
In practice, there's some pure Red areas in western NC but overall there's a lot of light red, blue and purple. It wouldn't be everyone in the State who was willing to secede and the fight would not be just between secessionists and Fort Bragg, but between secessionists and their neighbors.
In fact that's the way it is across much of the United States. The secessionist contingent seems to think the lines will be clear cut by State and or region. They won't be. If it comes, it'll be county against county against city. Neighborhood against neighborhood. Some places neighbor against neighbor.
If it comes, it may be really ugly.