Unquestionably the most effective piece of work he did that winter was the address at Cooper Institute, New York, on February 27. He had received an invitation in the fall of 1859 to lecture at Plymouth Church, Brooklyn. To his friends it was evident that he was greatly pleased by the compliment, but that he feared that he was not equal to an Eastern audience. After some hesitation he accepted, provided they would take a political speech if he could find time to get up no other. When he reached New York he found that he was to speak there instead of Brooklyn, and that he was certain to have a distinguished audience. Fearful lest he was not as well prepared as he ought to be, conscious, too, no doubt, that he had a great opportunity before him, he spent nearly all of the two days and a half before his lecture in revising his matter and in familiarizing himself with it. In order that he might be sure that he was heard he arranged with his friend, Mason Brayman, who had come on to New York with him, to sit in the back of the hall and in case he did not speak loud enough to raise his high hat on a cane.

Mr. Lincoln's audience was a notable one even for New York. It included William Cullen Bryant, who introduced him; Horace Greeley, David Dudley Field, and many more well known men of the day. It is doubtful if there were any persons present, even his best friends, who expected that Lincoln would do more than interest his hearers by his sound arguments. Many have confessed since that they feared his queer manner and quaint speeches would amuse people so much that they would fail to catch the weight of his logic. But to the surprise of everybody Lincoln impressed his audience from the start by his dignity and his seriousness. "His manner was, to a New York audience, a very strange one, but it was captivating," wrote an auditor. "He held the vast meeting spellbound, and as one by one his oddly expressed but trenchant and convincing arguments confirmed the soundness of his political conclusions, the house broke out in wild and prolonged enthusiasm. I think I never saw an audience more thoroughly carried away by an orator."

The Cooper Union speech was founded on a sentence from one of Douglas's Ohio speeches:—"Our fathers when they framed the government under which we live understood this question just as well, and even better, than we do now." Douglas claimed that the "fathers" held that the Constitution forbade the Federal government controlling slavery in the Territories. Lincoln with infinite care had investigated the opinions and votes of each of the "fathers"—whom he took to be the thirty-nine men who signed the Constitution—and showed conclusively that a majority of them "certainly understood that no proper division of local from Federal authority nor any part of the Constitution forbade the Federal government to control slavery in the Federal Territories." Not only did he show this of the thirty-nine framers of the original Constitution, but he defied anybody to show that one of the seventy-six members of the Congress which framed the amendments to the Constitution ever held any such view.

"Let us," he said, "who believe that 'our fathers who framed the government under which we live understood this question just as well, and even better, than we do now,' speak as they spoke, and act as they acted upon it. This is all Republicans ask—all Republicans desire—in relation to slavery. As those fathers marked it, so let it be again marked, as an evil not to be extended, but to be tolerated and protected only because of and so far as its actual presence among us makes that toleration and protection a necessity. Let all the guaranties those fathers gave it be not grudgingly, but fully and fairly, maintained. For this Republicans contend, and with this, so far as I know or believe, they will be content."

One after another he took up and replied to the charges the South was making against the North at the moment:—Sectionalism, radicalism, giving undue prominence to the slave question, stirring up insurrection among slaves, refusing to allow constitutional rights, and to each he had an unimpassioned answer inpregnable with facts.

The discourse was ended with what Lincoln felt to be a precise statement of the opinion of the question on both sides, and of the duty of the Republican party under the circumstances. This portion of his address is one of the finest early examples of that simple and convincing style in which most of his later public documents were written.

"If slavery is right," he said, "all words, acts, laws, and constitutions against it are themselves wrong, and should be silenced and swept away. If it is right, we cannot justly object to its nationality—its universality; if it is wrong, they cannot justly insist upon its extension—its enlargement. All they ask we could readily grant, if we thought slavery right; all we ask they could as readily grant, if they thought it wrong. Their thinking it right and our thinking it wrong is the precise fact upon which depends the whole controversy. Thinking it right, as they do, they are not to blame for desiring its full recognition as being right; but thinking it wrong, as we do, can we yield to them? Can we cast our votes with their views, and against our own? In view of our moral, social, and political responsibilities, can we do this?

"Wrong, as we think slavery is, we can yet afford to let it alone where it is, because that much is due to the necessity arising from its actual presence in the nation; but can we, while our votes will prevent it, allow it to spread into the national Territories, and to overrun us here in these free States? If our sense of duty forbids this, then let us stand by our duty fearlessly and effectively. Let us be diverted by none of those sophistical contrivances wherewith we are so industriously plied and belabored—contrivances such as groping for some middle ground between right and wrong: vain as the search for a man who should be neither a living man nor a dead man; such as a policy of 'don't care' on a question about which all true men do care; such as Union appeals beseeching true Union men to yield to Disunionists, reversing the divine rule, and calling, not the sinners, but the righteous to repentance; such as invocations to Washington, imploring men to unsay what Washington said and undo what Washington did.

"Neither let us be slandered from our duty by false accusations against us, nor frightened from it by menaces of destruction to the government, nor of dungeons to ourselves. Let us have faith that right makes might, and in that faith let us to the end dare to do our duty as we understand it."

From New York Lincoln went to New Hampshire to visit his son Robert, then at Phillips Exeter Academy. His coming was known only a short time before he arrived and hurried arrangements were made for him to speak at Concord, Manchester, Exeter and Dover. At Concord the address was made in the afternoon on only a few hours' notice; nevertheless, he had a great audience, so eager were men at the time to hear anybody who had serious arguments on the slavery question. Something of the impression Lincoln made in New Hampshire may be gathered from the following article, "Mr. Lincoln in New Hampshire," which appeared in the Boston "Atlas and Bee" for March 5: