It was altogether inevitable that the calmer consideration and the discussion of this matter should bring up new questions and create new situations. The Missouri Compromise had not yet been formally repealed. That Compromise forbade the creation of slave states out of any part of the Louisiana territory lying north of the southern line of Missouri, and by implication it forbade the carrying of slaves into any such territory prior to its admission as a state. Under the Compromise Missouri and Arkansas had been admitted to the Union as slave states and for thirty years the Compromise had stood as a bulwark against disunion. But now there appeared a tendency on the part of the territories lying north of the Missouri Compromise line to become populous. Emigration seemed to be setting in that direction and the fertility of the region promised presently to tempt great multitudes of men to settle there. That part of the territory which now constitutes Kansas was especially tempting to emigration. The eastern half of Kansas was a part of the Louisiana Purchase. Its western half was a part of the region acquired from Mexico. The eastern half of it, therefore, was subject to the Missouri Compromise's prohibition of slavery while the western half by virtue of the compromise measures of 1850 was free from that restriction. Out of all the conditions here briefly noted there arose at the South a clamor for the repeal of the Missouri Compromise. Men argued that as it was only a statute repealable at any session of Congress, and as, in their contention, it robbed and wronged the slave-holding half of the Union, it ought to be repealed. At the North it was felt that repeal would in effect make of slavery a national institution, and rob the anti-slavery sentiment of the benefit it had secured by consenting to the admission of Missouri and Arkansas as slave states. There was a very strong man in the Senate at that time, Stephen A. Douglas of Illinois. He was a born leader of men, a man of great ability and courage, and he had ambition to become president of the United States. He was a master of statecraft and an opportunist in politics. He had sought some years before to settle the question with regard to the new territories once for all by enacting a law to extend the Missouri Compromise line to the Pacific, thus excluding slavery north of that line from all the new as well as from all the older possessions of the Republic and by implication permitting it south of that line.