It is true that the proposal of their exclusion had failed to become law. But it had failed by a margin so narrow that its success might easily be anticipated as an event of the near future. It is true that neither the Wilmot Proviso nor any other legislation suggested at that time sought to forbid Southerners to migrate into the new territories. But it was proposed that they should be forbidden by law to take with them into those territories the slaves upon whose services they relied not only for agricultural work, but even more for that domestic service to which they had been accustomed all their lives to look for comfort. To tell them that they might remove their households into the new territories, but at the same time to say to them that they must leave behind all that had before contributed to their prosperity and to the comfort of their domestic arrangements, seemed to them something worse than a mockery. Out of the agitation of these questions arose very important events. The old sentiment at the South in favor of a gradual emancipation of the slaves, though it survived in some degree to the end, gave place, in large measure, to a new sentiment in behalf of slavery as a thing right in itself, a sentiment born of the instinct of self-preservation. The manifest disposition to exclude slavery from the newly acquired Southern possessions prompted the men of the South to question the Missouri Compromise itself. The spirit of that compromise had been that slave property might be taken into territories south of 36° 30´ north latitude, with the assurance that such territories might become slave states, in return for the stipulation of the South that all territory lying north of that line should be forever exempted from slavery. When the new territory was acquired from Mexico, a large part of it lying south of that line, it was naturally expected that in those regions the people of the slave states were to find an outlet for emigration as freely as those of the Northern states found a like outlet north of that line. When a determined effort was made, with every prospect of success, to deny even this to them, they began seriously to question a compromise by which they had surrendered so much and seemed now destined to gain so little. They had secured Arkansas and Missouri as outlets for their superfluous, discontented, unfortunate or specially enterprising population; they had surrendered all claim to an equal opportunity in Iowa, Kansas, Nebraska, Minnesota, the Dakotas and all the rest of the rich regions embraced in the Louisiana Purchase. Obviously, it seemed to them, they had made a bad bargain, and now that they were threatened with a denial of their share in the benefits of it, so far as the territory acquired from Mexico was concerned, they were disposed to repent them of it or at the very least to question the extent to which its terms were binding on themselves.