“But let’s not be blind to what the very politicians who made the decisions wrote down!”
If Lincoln was planning to fight over the issue of slavery, we should be able to read Lincoln’s first inaugural address and confirm it.
I can’t find the language. Can you?
Another logical fallacy - you’re zero for two.
Your point is too subtle here. Most people are not aware that Lincoln said he had no objections to the Corwin Amendment. They don't know about the Amendment, and they don't know that Lincoln tacitly supported it.
They don't realize how contrary this is to the narrative because they aren't aware of any of this. You have to explicitly spell it out for them in order for them to comprehend it.
People who know about it can get your point. It simply goes over the head of those people (most) who do not know about it.
But you are throwing out a red herring by pointing this out. The guys who voted for secession had slavery on their minds--they said as much in a ton of documents. You can talk about States' Rights--but then will you then consider just which rights were being debated?
Don't assume that the two sides of a war share the same rationale in going to war.
The Federal Government went to war to preserve the Union. Along the way, the President decided that the abolition of chattel slavery was a means (perhaps an indispensable one) to achieve that end and preserve the results. Once Emancipation was a matter of policy, Lincoln short-circuited any serious talk of foreign intervention on behalf of the Confederacy. And then the Union Army got 180,000 black men to help swell its ranks.