For four or five years after his return from Congress, Lincoln remained in Springfield, working industriously at his profession. He was offered a law partnership in Chicago, but declined on the ground that his health would not stand the confinement of a great city. His business increased in volume and importance as the months went by; and it was during this time that he engaged in what is perhaps the most dramatic as well as the best known of all his law cases—his defense of Jack Armstrong's son on a charge of murder. A knot of young men had quarreled one night on the outskirts of a camp-meeting, one was killed, and suspicion pointed strongly toward young Armstrong as the murderer. Lincoln, for old friendship's sake, offered to defend him—an offer most gratefully accepted by his family. The principal witness swore that he had seen young Armstrong strike the fatal blow—had seen him distinctly by the light of a bright moon. Lincoln made him repeat the statement until it seemed as if he were sealing the death-warrant of the prisoner. Then Lincoln began his address to the jury. He was not there as a hired attorney, he told them, but because of friendship. He told of his old relations with Jack Armstrong, of the kindness the prisoner's mother had shown him in New Salem, how he had himself rocked the prisoner to sleep when the latter was a little child. Then he reviewed the testimony, pointing out how completely everything depended on the statements of this one witness; and ended by proving beyond question that his testimony was false, since, according to the almanac, which he produced in court and showed to judge and jury, THERE WAS NO MOON IN THE SKY THAT NIGHT at the hour the murder was committed. The jury brought in a verdict of "Not guilty," and the prisoner was discharged.
Lincoln was always strong with a jury. He knew how to handle men, and he had a direct way of going to the heart of things. He had, moreover, unusual powers of mental discipline. It was after his return from Congress, when he had long been acknowledged one of the foremost lawyers of the State, that he made up his mind he lacked the power of close and sustained reasoning, and set himself like a schoolboy to study works of logic and mathematics to remedy the defect. At this time he committed to memory six books of the propositions of Euclid; and, as always, he was an eager reader on many subjects, striving in this way to make up for the lack of education he had had as a boy. He was always interested in mechanical principles and their workings, and in May, 1849, patented a device for lifting vessels over shoals, which had evidently been dormant in his mind since the days of his early Mississippi River experiences. The little model of a boat, whittled out with his own hand, that he sent to the Patent Office when he filed his application, is still shown to visitors, though the invention itself failed to bring about any change in steamboat architecture.
In work and study time slipped away. He was the same cheery companion as of old, much sought after by his friends, but now more often to be found in his office surrounded by law-books and papers than had been the case before his term in Congress. His interest in politics seemed almost to have ceased when, in 1854, something happened to rouse that and his sense of right and justice as they had never been roused before. This was the repeal of the "Missouri Compromise," a law passed by Congress in the year 1820, allowing Missouri to enter the Union as a slave State, but positively forbidding slavery in all other territory of the United States lying north of latitude 36 degrees 30 minutes, which was the southern boundary-line of Missouri.
Up to that time the Southern States, where slavery was lawful, had been as wealthy and quite as powerful in politics as the Northern or free States. The great unoccupied territory lying to the west, which, in years to come, was sure to be filled with people and made into new States, lay, however, mostly north of 36 degrees 30 minutes; and it was easy to see that as new free States came one after the other into the Union the importance of the South must grow less and less, because there was little or no territory left out of which slave States could be made to offset them. The South therefore had been anxious to have the Missouri Compromise repealed.
The people of the North, on the other hand, were not all wise or disinterested in their way of attacking slavery. As always happens, self-interest and moral purpose mingled on both sides; but, as a whole, it may be said that they wished to get rid of slavery because they felt it to be wrong, and totally out of place in a country devoted to freedom and liberty. The quarrel between them was as old as the nation, and it had been gaining steadily in intensity. At first only a few persons in each section had been really interested. By the year 1850 it had come to be a question of much greater moment, and during the ten years that followed was to increase in bitterness until it absorbed the thoughts of the entire people, and plunged the country into a terrible civil war.
Abraham Lincoln had grown to manhood while the question was gaining in importance. As a youth, during his flatboat voyages to New Orleans he had seen negroes chained and beaten, and the injustice of slavery had been stamped upon his soul. The uprightness of his mind abhorred a system that kept men in bondage merely because they happened to be black. The intensity of his feeling on the subject had made him a Whig when, as a friendless boy, he lived in a town where Whig ideas were much in disfavor. The same feeling, growing stronger as he grew older, had inspired the Lincoln-Stone protest and the bill to free the slaves in the District of Columbia, and had caused him to vote at least forty times against slavery in one form or another during his short term in Congress. The repeal of the Missouri Compromise, throwing open once more to slavery a vast amount of territory from which it had been shut out, could not fail to move him deeply. His sense of justice and his strong powers of reasoning were equally stirred, and from that time until slavery came to its end through his own act, he gave his time and all his energies to the cause of freedom.
Two points served to make the repeal of the Missouri Compromise of special interest to Lincoln. The first was personal, in that the man who championed the measure, and whose influence in Congress alone made it possible, was Senator Stephen A. Douglas, who had been his neighbor in Illinois for many years.
The second was deeper. He realized that the struggle meant much more than the freedom or bondage of a few million black men: that it was in reality a struggle for the central idea of our American republic—the statement in our Declaration of Independence that "all men are created equal." He made no public speeches until autumn, but in the meantime studied the question with great care, both as to its past history and present state. When he did speak it was with a force and power that startled Douglas and, it is said, brought him privately to Lincoln with the proposition that neither of them should address a public meeting again until after the next election.
Douglas was a man of great ambition as well as of unusual political skill. Until recently he had been heartily in favor of keeping slavery out of the Northwest Territory; but he had set his heart upon being President of the United States, and he thought that he saw a chance of this if he helped the South to repeal the Missouri Compromise, and thus gained its gratitude and its votes. Without hesitation he plunged into the work and labored successfully to overthrow this law of more than thirty years' standing.
Lincoln's speech against the repeal had made a deep impression in Illinois, where he was at once recognized as the people's spokesman in the cause of freedom. His statements were so clear, his language so eloquent, the stand he took so just, that all had to acknowledge his power. He did not then, nor for many years afterward, say that the slaves ought to be immediately set free. What he did insist upon was that slavery was wrong, and that it must not be allowed to spread into territory already free; but that, gradually, in ways lawful and just to masters and slaves alike, the country should strive to get rid of it in places where it already existed. He never let his hearers lose sight of the great underlying moral fact. "Slavery," he said, "is founded in the selfishness of man's nature; opposition to it in his love of justice." Even Senator Douglas was not prepared to admit that slavery was right. He knew that if he said that he could never be President, for the whole North would rise against him. He wished to please both sides, so he argued that it was not a question for him or for the Federal Government to decide, but one which each State and Territory must settle for itself. In answer to this plea of his that it was not a matter of morals, but of "State rights"—a mere matter of local self-government—Mr. Lincoln replied, "When the white man governs himself that is self-government; but when he governs himself and also governs another man, that is more than self-government—that is despotism."