“Unilateral secession doesn’t work. It doesn’t provide an authoritative and accepted structure to settle things.”
And war does?
Good point. So why did the south start one?
It's what experience has taught us to expect. And yes, wars do settle things. Though it would have been better to do so peacefully and avoid violence.
Henry Clay knew that. Daniel Webster knew that. Most thinking people in the 1850s and 1850s had an inkling.
Even the moron who said he would drink every drop of blood shed because of secession (or wipe it up with his handkerchief) knew about the possibility before rejecting it.
What's the use of not learning from history? Why pretend to be (or be) ignorant?