About William H. Seward:
William Henry Seward was United States Secretary of State from 1861 to 1869, and also served as Governor of New York and United States Senator. A determined opponent of the spread of slavery in the years leading up to the American Civil War, he was a dominant figure in the Republican Party in its formative years. Although regarded as the leading contender for the party's presidential nomination in 1860, he was defeated by Abraham Lincoln.
But you answer, that the Constitution recognizes property in slaves. It would be sufficient, then, to reply, that this constitutional recognition must be void, because it is repugnant to the law of nature and of nations.William H. Seward
But assuming the same premises, to wit, that all men are equal by the law of nature and of nations, the right of property in slaves falls to the ground; for one who is equal to another cannot be the owner or property of that other.William H. Seward
If slavery, limited as it yet is, now threatens to subvert the Constitution, how can we as wise and prudent statesmen, enlarge its boundaries and increase its influence, and thus increase already impending dangers?William H. Seward
The proposition of an established classification of states as slave states and free states, as insisted on by some, and into northern and southern, as maintained by others, seems to me purely imaginary, and of course the supposed equilibrium of those...William H. Seward