I stand corrected. 2/3rds is still a supermajority. It leaves no doubt that the majority of the states' representatives and Senators agreed to this.
Only enough Republicans voted for the Amendment to ensure its passage by the narrowest of margins.
This is what the liberal party always has done with votes it thinks will be unpopular with it's constituency.
Passage and ratifiction of the Corwin Amendment would never have won back the Deep South states which had already seceded, but it was believed that it could have pursuaded those in the Upper South to remain in the union.
Well this assertion is seemingly contradicted by Lincoln's activities in sending notification to the governors of those already seceded states as well as the upper southern states. If Lincoln did not think it would win them back, why did he try?
There was no guarantee that the amendment would be ratified, though.
Pretty good guarantee. William Seward assured everyone that New York would pass it, and if New York passed it, all it's satellite states would have followed suit. Add those to the then existing 15 slave states (later 16 slave states), and it's chances of passage were very good. Five Northern states already passed it.
It was a lock.
You and I will never have to make such difficult and weighty decisions as those in the past did, so it's best not to speak to lightly about the choices that they made when constrained by circumstances we will never have to face.
One of the reasons why I focus so much of my discussion time on the Civil War is because I see the parallels to today. I have reached the point where I think the original civil war never ended, it just went to a slow burn. The issues bedeviling the nation in that era are still bedeviling us today, and Washington DC is still the focus of everything wrong in the nation.
Only three free states ratified the Amendment — Ohio, Rhode Island, and Michigan — and two slave states — Maryland and Kentucky (so did the Unionist government of Virginia that later became West Virginia, but that may not have counted).
The chances the amendment would pass the legislatures the remaining states weren't good. A 3/4ths majority was required and there was enough anti-slavery sentiment to shoot down the amendment or delay it to the point were it would be moot.
33 or 34 states at the time. 26 or 27 still in the union. Depending on which figure you use that means that 9 or 7 states could defeat or delay the amendment. Maybe my math is wrong, but it was anything but a lock.
It's strange that you are so cynical but take Seward at his word. He was trying to sell the amendment, so of course he made claims for it that exaggerated its strength.