If he had not had an anti-slavery plank in his platform, there would have been no threat to the Union.
HIs obvious intent to end slavery caused the threat to the Union.
I can see why you want me to STFU, as it is very easy for me to reveal that you are full of shit.
His intent was to save the Union. He never placed anything else above that in order of importance.
The south fought for their "states rights" and their intent to expand to slavery to the northern states or seceed and maintain it in the south.
And I don't care if you STFU or not. It is your right to continue to look like a dumbass.
If Lincoln got his way, as expressed in this 1860 campaign platform, and prevented slavery from being expanded to new states, this would have quickly led to the Free States gaining unchecked dominance in Congress and a lock on the Presidency, leading to an ever increasingly hostile to slavery, Federal Government.
The election of Lincoln was an existential threat to the political and economic elite of the South, of that time, as their whole class was based on slavery.
He talked some diplomatic and/or political smack down the road to try to walk that back, when it was called for, but no one with any sense would ignore his actions and believe those statements.