[HandyDandy]

I see Lincoln's letter to Greeley as Abe saying that paramount to him was saving the Union, and that if he could do it by involving slavery, he would. Surely you can see in that letter he had three options (not just the one that you bolded) for saving the Union by using the peculiar institution as leverage. He made it clear to Greeley what options were on the table. We both know which option he took. So clearly, Abe wasn't merely trying to justify, after the fact, his purpose in the 2nd Innaugural.

Not to mention, I have yet to look up the letter from Greeley that Abe was responding to.

[DiogenesLamp]

Surely you can see in that letter he had three options (not just the one that you bolded) for saving the Union by using the peculiar institution as leverage.

You are portraying the abolition of slavery as "optional" rather than the purpose of the war. You made my case for me. Thank you.

[x]

Not to mention, I have yet to look up the letter from Greeley that Abe was responding to.

The "Prayer of Twenty Millions" was an open letter published in the paper. Probably, Greeley also sent a copy to Lincoln. You can find it here.

A lot of Lincoln's literary fame may have to do with his ability to condense his thoughts into a few well chose words, rather than to sprawl out as Greeley does.