Except secession in the manner which they chose to pursue it is not lawful or Constitutional.
Only to unlawfully become the target of Northern aggression and invasion by the Union Army.
Are you forgetting that little matter of bombarding Fort Sumter into submission? Without that there wouldn't have been a war and there would have been no reason for anybody to invade anyone.
It was a terrible time in our history, all deaths were unnecessary, but Lincoln was going to have his way, come hell or high water. What a horrible price was paid for his tyranny.
Shouldn't blame lie with those who started the war?
As has been posted before, Lincoln sent the US Navy to re-supply, though the Sumter garrison was getting foodstuffs from on shore.
Abe was flicking boogers at what he thought were push-overs.
300,000 plus dead guys under his direct command showed what a n00b fool he was...
No doubt about it, you and I just disagree on who that was.