“We didn’t secede from Great Britain, we revolted. “
Well that’s a classic for being a distinction without a difference.
And what exactly do you think was the moral right for the colonials to secede from Britain?
Now we've had this discussion many times and you full well know the answer, even if some others don't.
The fact is our Founders fully understood there were two, and only two, conditions which fully justified, in their word, disunion: 1) mutual consent and 2) "abuses and usurpations" having that same effect.
In Madison's words:
Virginia's ratification statement uses the words, "injury or oppression" and New York's simplifies them to one word, "necessary".
But no Founder advocated or accepted the idea of secession "at pleasure" meaning without either mutual consent or necessity from abuses.
And, as it happened, in our Founders' case both legitimate reasons for disunion happened: first in 1776 by the necessity of abuses and usurpations from British King George (as spelled out in their DOI) and second in 1788 by mutual consent (ratification) of all the parties.
So our Founders were very clear on this subject and built into their Constitution protections not only against foreign invasion, but also against rebellion, insurrection, "domestic violence" and treason.
When Deep South states declared their secession "at pleasure" they violated Founders' Original Intent, but did not immediately commit rebellion, insurrection, domestic violence, invasion or treason.
However, within just a few weeks and months they committed all of those in provoking, starting, formally declaring and waging war against the United States in Union states.
President Lincoln's response to those acts was entirely in keeping with both spirit and letter of the Constitution Founders' Original Intent.
But there have to be a legitimate cause to do so.
The South just didn't like the results of an election.
The moral right for the colonies was laid out clearly in the Declaration, justifying the revolution.