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.

There is no line, straight or crooked, suitable for a national boundary
upon which to divide. Trace through, from east to west, upon the line
between the free and slave country, and we shall find a little more than
one-third of its length are rivers, easy to be crossed, and populated,
or soon to be populated, thickly upon both sides; while nearly all its
remaining length are merely surveyors' lines, over which people may walk
back and forth without any consciousness of their presence. No part of
this line can be made any more difficult to pass by writing it down on
paper or parchment as a national boundary. The fact of separation, if it
comes, gives up on the part of the seceding section the fugitive-slave
clause, along with all other constitutional obligations upon the section
seceded from, while I should expect no treaty stipulation would ever be
made to take its place.

But there is another difficulty. The great interior region bounded east
by the Alleghanies, north by the British dominions, west by the Rocky
Mountains, and south by the line along which the culture of corn and
cotton meets, and which includes part of Virginia, part of Tennessee,
all of Kentucky, Ohio, Indiana, Michigan, Wisconsin, Illinois, Missouri,
Kansas, Iowa, Minnesota, and the Territories of Dakota, Nebraska, and
part of Colorado, already has above 10,000,000 people, and will have
50,000,000 within fifty years if not prevented by any political folly or
mistake. It contains more than one-third of the country owned by the
United States--certainly more th