The whole slavery issue, which is the most disastrous mistake in U.S. history, should have been dealt with decisively at the time of ratification of the Constitution. Sane and ethical leaders like VA's Washington (our real greatest President) wanted to phase out slavery, starting with an end to the slave trade and it's exclusion from new territories. The extreme Southern states refused to accept any restrictions. Why? For the same basic reason Jorge and others want amnesty for Hispanic illegals: Blacks could be made to do "the work white Americans wouldn't do." Land was nearly free and abundant, so each white could have his own farm. No white would work as serf on a malarial plantation. So in order that an elite could enjoy an aristocratic lifestyle on the backs of others and "generate wealth," slavery was allowed to continue. The result was example of what happens when short-term economic considerations and greed triumph over ethics and national interest.
I don't think we disagree on that. My point is that the result was one that the Confederacy provoked.
Davis fired on Sumter in part because he was afraid the South Carolinians would do it with out him and in part because he thought the Northern reaction would drive the upper tier of slave states into the Confederacy, which it did.
Secession was a very sketchy business. Historians have had a hard time trying to figure out whether Georgia's secession really resulted in a valid win for the secessionists. Virginia's convention rejected secession, and then, in the panic over Sumter and the Union draft, accepted it.
North Carolina voters rejected a secession convention in February, and the legislature called on in May, which passed an Ordinance of Secession, which was never submitted to the people in a referendum. Arkansas's convention rejected secession in March and called for a referendum in August, then voted for secession in May. The referendum was never held.
Even if you assume that unilateral secession was constitutional, there was room for controversy over these rushed secession resolutions. Davis was willing to do everything he could to weaken the Union. That's what I meant by "smash and grab." The country didn't go through a reasoned process of deliberation about union or disunion. The process was rushed and forced by secessionist elements, so that they could pick up the pieces themselves.