...allow the people of VA, SC,? ... AL, GA, etc to secede if they wanted to?

If "of the people and by the people" is important then the people of those states should choose and Lincoln should have respect their right to be free and determine their own destiny. Right?

If you disagree, where in the Constitution is leaving "outlawed." And, if the Court had enough Southern Justices, they would have approved secession. But, the Court was stacked with Yankees who acted like tyrants and dictators. Right?