U. S. Grant
"The cause of the great War of the Rebellion against the United Status will have to be attributed to slavery. For some years before the war began it was a trite saying among some politicians that "A state half slave and half free cannot exist." All must become slave or all free, or the state will go down. I took no part myself in any such view of the case at the time, but since the war is over, reviewing the whole question, I have come to the conclusion that the saying is quite true.
Slavery was an institution that required unusual guarantees for its security wherever it existed; and in a country like ours where the larger portion of it was free territory inhabited by an intelligent and well-to-do population, the people would naturally have but little sympathy with demands upon them for its pro- tection. Hence the people of the South were dependent upon keeping control of the general government to secure the perpetuation of their favorite institution. They were enabled to maintain this control long after the States where slavery existed had ceased to have the controlling power, through the assistance they received from odd men here and there throughout the Northern States. They saw their power waning, and this led them to encroach upon the prerogatives and independence of the Northern States by enacting such laws as the Fugitive Slave Law. By this law every Northern man was obliged, when properly summoned, to turn out and help apprehend the runaway slave of a Southern man. Northern marshals became slave-catchers, and Northern courts had to contribute to the support and protection of the institution.
This was a degradation which the North would not permit any longer than until they could get the power to expunge such laws from the statute books. Prior to the time of these encroachments the great majority of the people of the North had no particular quarrel with slavery, so long as they were not forced to have it themselves. But they were not willing to play the role of police for the South in the protection of this particular institution."
--U.S. Grant
Grant continued:
"The framers were wise in their generation and wanted to do the very best possible to secure their own liberty and independence, and that also of their descendants to the latest days. It is preposterous to suppose that the people of one generation can lay down the best and only rules of government for all who are to come after them, and under unforeseen contingencies...We could not and ought not to be rigidly bound by the rules laid down under circumstances so different for emergencies so utterly unanticipated. The fathers themselves would have been the first to declare that their prerogatives were not irrevocable. They would surely have resisted secession could they have lived to see the shape it assumed."