I would be interested if you could find somewhere, anywhere, that I said, “the North invaded the South to destroy slavery.”
The Union side fought the entire war to preserve the Union. A convenient side effect of the war was that it destroyed slavery. In fact, once the war started there were only really three options with regard to the institution:
1. A quick Union victory would have resulted in temporary continuance of slavery, probably with increasing and gradually strangling restrictions. For instance, Congress could have, entirely constitutionally, prohibited commerce in slaves between the states. Shut up separately within states, the institution would have withered away.
2. A CSA victory would of course have resulted in slavery’s continuance for an indefinite period. I assume it would still have been abolished by the turn of the century or thereabouts, though quite possibly with some sort of nonsense about “apprenticeships” or such, as was tried unsuccessfully in the British colonies.
3. A long war resulting in an eventual Union victory. This would have inevitably resulted in abolition. No way the South gets to keep its slaves after starting such a horrible war to protect slavery. (That would have been the Union belief, anyway.)
CSA apologists often try a remarkably dishonest rhetorical trick. If one agrees that there were other issues than slavery involved in the regional dispute and the war, they think they’ve scored some sort of debating victory. But of course in the history of the world there has never been a war fought with unmixed motives. IOW, they try to erect the straw man that those who are not apologists for the CSA believe the war was ONLY about slavery.
To be fair, there are those on the Left who agree with them. Recognizing that the fight against slavery would have the US government fighting in a noble cause, (and we can’t have that) they insist that slavery was merely a side issue in the class struggle, or some such nonsense.
There you go. That is the truth as I understand it. And this brings us back to my initial point.
It is Ironic that Abe Lincoln would reference the Declaration of Independence while engaging in a fight to prevent Independence for others. He was playing the King George III role in this drama.