We were taught that war could range from high intensity to low intensity. It can be low intensity and covert. Imagining a definition for low intensity, covert war is a good mental exercise.
You could say we were in the civil war years prior to Fort Sumpter. The tensions were high enough.
But the first battle of Fort Sumpter is when most peope think the actual Civil WAr began.
I don't believe we have had a new Fort Sumpter yet. Nor do we have a declared civil war.
Yet.