"I say, then, sir, that the rule by which to judge of the intent, the object, the purpose of an act, is to see what the act is calculated to do, what its natural tendency is, what will in all human probability be the effect. Before the passage of the Kansas-Nebraska act, there stood upon your statute-book a law by which slavery was prohibited from going into any territory north of 36° 30'. The validity and constitutionality of that law had been recognized by repeated decisions of the courts of the several States. If I am not mistaken, I have a memorandum by me, showing that it had been recognized by the Supreme Court of the State of Louisiana. So far as I know, the constitutionality of that enactment was unquestioned, and the country had reposed in peace for more than a generation under its operation. By and by, however, it was discovered to be unconstitutional, and it was broken down. The instant it was broken down, slavery went into Kansas; but still, gentlemen tell us they did not intend to let slavery in; that was not the object. Let me illustrate this. Suppose a farmer has a rich field, and a pasture adjoining, separated by a stonewall which his fathers had erected there thirty years before. The wall keeps out the cattle in the pasture, who are exceedingly anxious to get into the field. Some modern reformer thinks that moral suasion will keep them in the pasture, even if the wall should be taken down, and he proceeds to take it down. The result is, that the cattle go right in; the experiment fails. The philosopher says; 'Do not blame me; that was not my intention; but it is true, the effect has followed.' I retort upon him; 'You knew the effect would follow; and, knowing that it would follow, you intended that it should follow.' * * * * * "This brings me to another part of my subject, in answer to a question which the honorable senator from Illinois (Mr. Douglas) propounded, when he asked if he was to be read out of the party for a difference on this point. I have great regard for the sagacity of that honorable senator, but I confess it was a little shaken when he asked that question; is a man to be read out of the party for departing from the President on this great cardinal point? Why, sir, he asks, is a man who differs from the President on the Pacific railroad to go out of the party? Oh no, he may stay. If he differs on Central America, very good; take the first seat if you please. You may differ with the President on anything and everything but one, and that is this sentiment, which I shall read; Mr. Buchanan shall speak his own creed. On the 19th of August 1842, in the Senate, Mr. Buchanan used this language: