Wrong. Lacking the votes the north, under Buchanan and carried forward by Lincoln, did nothing until attacked by the rebels.
Your attempts to distort by broad-brush noted, you would have us believe that there was some sort of concerted effort toward national emancipation. There wasn't. Northern states had largely resolved the issue internally (state by state) through legislation. In their view how the southern state conducted their affairs was their own business.
A state of detente have been achieved between slave states and free states, there was no urgency to do anything more until the southern fire-eaters launched their Civil War against the north.
If what you say is true - and you make a fair case - then we can dismiss the notion that the north was fighting for some high moral cause like “freeing the slaves.”
The slogan, “as he died to make men holy, let us die to make men free” can more rightly be seen - if you are correct - as a “moral” pretext for war by the north.