How about they never introduced such an amendment because prior to the rebellion such an amendment would have needed 46 states to ratify it assuming the 15 slave states all voted the ratification down? Do the math.
I leap to the conclusion Lincoln and his auxiliaries did not have the votes to peacefully pass the amendment it is sometimes claimed he wanted.
What Lincoln needed to “free the slaves” was war.
But first he would need a pretext for war. Which his navy found in the Gulf of Tonkin Incident. I meant to say, the Fort Sumter Incident.