There are men who, with clear perceptions, as they think, of their own duty, do not see how too eager a pursuit of one duty may involve them in the violation of others, or how too warm an embracement of one truth may lead to a disregard of other truths just as important.  As I heard it stated strongly, not many days ago, these persons are disposed to mount upon some particular duty, as upon a war-horse, and to drive furiously on and upon and over all other duties that may stand in the way.  There are men who, in reference to disputes of that sort, are of opinion that human duties may be ascertained with the exactness of mathematics.  They deal with morals as with mathematics; and they think what is right may be distinguished from what is wrong with the precision of an algebraic equation.  They have, therefore, none too much charity toward others who differ from them.  They are apt, too, to think that nothing is good but what is perfect, and that there are no compromises or modifications to be made in consideration of difference of opinion or in deference to other men’s judgment.  If their perspicacious vision enables them to detect a spot on the face of the sun, they think that a good reason why the sun should be struck down from heaven.  They prefer the chance of running into utter darkness to living in heavenly light, if that heavenly light be not absolutely without any imperfection. * * *

But we must view things as they are.  Slavery does exist in the United States.  It did exist in the States before the adoption of this Constitution, and at that time.  Let us, therefore, consider for a moment what was the state of sentiment, North and South, in regard to slavery,—­in regard to slavery, at the time this Constitution was adopted.  A remarkable change has taken place since; but what did the wise and great men of all parts of the country think of slavery then?  In what estimation did they hold it at the time when this Constitution was adopted?  It will be found, sir, if we will carry ourselves by historical research back to that day, and ascertain men’s opinions by authentic records still existing among us, that there was no diversity of opinion between the North and the South upon the subject of slavery.  It will be found that both parts of the country held it equally an evil, a moral and political evil.  It will not be found that, either at the North or at the South, there was much, though there was some, invective against slavery as inhuman and cruel.  The great ground of objection to it was political; that it weakened the social fabric; that, taking the place of free labor, society became less strong and labor less productive; and therefore we find from all the eminent men of the time the clearest expression of their opinion that slavery is an evil.  They ascribed its existence here, not without truth, and not without some acerbity of temper and force of language, to the injurious policy of the mother country, who, to favor the navigator, had entailed