In 1854 the moral sense of the nation was shocked by the repeal of what is called "The Missouri Compromise." That was a law passed in 1820 for the admission of the Territory of Missouri to the Union as a slave State, upon a condition that slavery should not go north of its northern boundary, latitude 36° 30'. Lincoln shared the national indignation. Douglas, then in the United States Senate, was one of the advocates of the repeal, and his powerful influence in Congress made it possible. As soon as the action of Congress was announced, the entire country was plunged into a discussion of the question on the platform, in the pulpit, in the press, in the debating societies, by the firesides, at the corner groceries, at the post-office, and wherever people met together. Lincoln took no public part in the controversy for several months, but during the interval studied the question in its moral, historical, and constitutional bearings, and while the Democrats accused him of "mousing around" the libraries of the State-House, he was preparing himself for a controversy which he knew was sure to come. That fall (1854) Richard Yates was up for Congress and Lincoln took the stump in his behalf. In the mean time Mr. Douglas was speaking in other sections of the State, but came to Springfield to attend the State Agricultural Fair, and, being a United States Senator and a political idol, was of course a great attraction. He made a speech justifying the action of Congress, and, by common impulse, the opponents of the repeal called upon Lincoln to answer him. There is no doubt of the zeal and ardor with which he accepted the invitation, and he spoke for four hours, as one of his friends testifies, "in a most happy and pleasant style, and was received with abundant applause." At times he made statements which brought Senator Douglas to his feet, and their passages at arms created much excitement and enthusiasm. It was evident that the force of Lincoln's argument surprised and disconcerted Mr. Douglas, for he insisted upon making a two-hours' rejoinder, which of itself was a confession of his defeat.