"An Impassable Wall" Trump? No, Lincoln

 Physically speaking, we can not separate. We can not remove our respective sections from each other nor build an impassable wall between them. A husband and wife may be divorced and go out of the presence and beyond the reach of each other, but the different parts of our country can not do this. They can not but remain face to face, and intercourse, either amicable or hostile, must continue between them, Is it
possible, then, to make that intercourse more advantageous or more satisfactory after separation than before? Can aliens make treaties easier than friends can make laws? Can treaties be more faithfully enforced between aliens than laws can among friends? Suppose you go to war, you can not fight always; and when, after much loss on both sides and no gain on either, you cease fighting, the identical old questions, as to terms of intercourse, are again upon you.

Is it doubted, then, that the plan I propose, if adopted, would shorten the war, and thus lessen its expenditure of money and of blood? Is it doubted that it would restore the national authority and national prosperity and perpetuate both indefinitely? Is it doubted that we here--Congress and Executive can secure its adoption? Will not the good people respond to a united and earnest appeal from us? Can we, can they, by any other means so certainly or so speedily assure these vital objects? We can succeed only by concert. It is not "Can any of us imagine better?" but "Can we all do better?" Object whatsoever is possible, still the question recurs, "Can we do better?" The dogmas of the quiet past are inadequate to the stormy present. The occasion is piled high with difficulty, and we must rise with the occasion. As our case is new, so we must think anew and act anew. We must disenthrall ourselves, and then we shall save our country.

Fellow-citizens, we can not escape history. We of this Congress and this Administration will be remembered in spite of ourselves. No personal significance or insignificance can spare one or another of us. The fiery trial through which we pass will light us down in honor or dishonor to the latest generation. We say we are for the Union. The world will not forget that we say this. We know how to save the Union. The world knows we do know how to save it. We, even we here, hold the power and bear the responsibility. In giving freedom to the slave we assure freedom to the free--honorable alike in what we give and what we preserve. We shall nobly save or meanly lose the last best hope of earth. Other means may succeed; this could not fail. The way is plain, peaceful, generous, just--a way which if followed the world will forever applaud and God must forever bless.

http://www.presidency.ucsb.edu/ws/?pid=29503