[CobaltBlue]

"How it could be at once eradicated" meant abolished -- and Clay knew, as Lincoln knew, that, as a practical matter, abolition would lead to civil war.

Which is why he did not want to start a civil war, and why he said he would not start a civil war, and why he did not start the Civil War.

Lincoln was not an abolitionist. He wanted to contain slavery in the South.

[eleni121]

Although not one at first, Lincoln certainly evolved into being an abolitionist.

[nolu chan]

"How it could be at once eradicated" meant abolished -- and Clay knew, as Lincoln knew, that, as a practical matter, abolition would lead to civil war.

Cast into life where slavery was already widely spread and deeply seated, he did not perceive, as I think no wise man has perceived, how it could be at once eradicated, without producing a greater evil, even to the cause of human liberty itself.

"at once eradicated" most definitely means non-gradual abolition. However, that is not the question. The question was what Lincoln believed to be a greater evil than the institution of slavery, a greater threat to the cause of human liberty.

Lincoln clearly says something, compared to slavery, is a greater evil, even to the cause of human liberty itself.

What was that something, in Lincoln's mind, that was a greater evil than the institution of slavery?

The correct answer is not civil war. Lincoln was reaffirming the long-held beliefs of Henry Clay in a eulogy in 1852 and restated it again in 1854.

Lincoln was not an abolitionist. He wanted to contain slavery in the South.

Lincoln was a racial separatist. He wanted to export the entire Black population.