No more vital interest that were threatened by the North. Yet the Confederacy felt that Fort Sumter was worth a war. And they acted unwisely.
You don't think having guns threatening your shipping in one of your most important port cities is not a vital interest? Especially given the fact that Northern newspapers had already called for those guns to be used against the port itself?
"With regard to the customs revenues in South Carolina, it may be questionable whether the best plan is to send a new collector or to repeal the acts creating the several ports of entry on the coast of South Carolina. This latter arrangement would avoid the collision of two sets of officers, and would prevent trade with foreign countries. It would be proper, we suppose, to prohibit coast-wise trade to and from the ports of South Carolina, whilst she is in her present attitude of armed defiance of the United States. In the enforcement of the revenue laws, the forts become of primary importance. Their guns cover just so much ground as is necessary to enable the United States to enforce their laws."Philadelphia Press, January 15, 1861