“Lincoln offered a constitutional amendment which would have expressly protected slavery.”
Wrong, Lincoln couldn’t offer up an amendment, he was not a member of the Congress of the United States.
Wrong. Everybody understood Lincoln's feigned ignorance was just that. What he was extending in his inaugural address was an offer. The quid pro quo was slavery effectively forever in exchange for the original 7 states re-entry into the union. They turned it down.
and by the way, it had already passed the House and the Senate with the necessary 2/3rds supermajority AFTER the Southern delegation had withdrawn.