When the Mexican territory was acquired, Stephen A. Douglas, as the experienced chairman of the Committee on Territories in the Senate, was already developing a theory respecting slavery in the Territories which was destined to play a leading part in the later crusade against slavery. Douglas was the most thoroughgoing of expansionists and would acknowledge no northern boundary on this side of the North Pole, no southern boundary nearer than Panama. He regarded the United States, with its great principle of local autonomy, as fitted to become eventually the United States of the whole world, while he held it to be an immediate duty to make it the United States of North America. As the son-in-law of a Southern planter in North Carolina, and as the father of sons who inherited slave property, Douglas, although born in Vermont, knew the South as did no other Northern statesman. He knew also the institution of slavery at first hand. As a pronounced expansionist and as the congressional leader in all matters pertaining to the Territories, he acquired detailed information as to the qualities of these new possessions, and he spoke, therefore, with a good degree of authority when he said, "If there was one inch of territory in the whole of our acquisitions from Mexico where slavery could exist, it was in the valleys of the Sacramento and the San Joaquin." But this region was at once preempted for freedom upon the discovery of gold. Douglas did not admit that even the whole of Texas would remain dedicated to slavery. Some of the States to be formed from it would be free, by the same laws of climate and resources which determined that the entire West would remain free. Before the Mexican War the Senator had become convinced that the extension of slavery had reached its limit; that the Missouri Compromise was a dead letter except as a psychological palliative; that Nature had already ordained that slave labor should be forever excluded from all Western territory both north and south of that line. His reply to Calhoun's contention that a balance must be maintained between slave and free States was that he had plans for forming seventeen new States out of the vast Western domains, every one of which would be free. And besides, said he, "we all look forward with confidence to the time when Delaware, Maryland, Virginia, Kentucky, and Missouri, and probably North Carolina and Tennessee will adopt a gradual system of emancipation." Douglas was one of the first to favor the admission of California as a free State. According to the Missouri Compromise law and the laws of Mexico, all Western territory was free, and he was opposed to interference with existing conditions. The Missouri Compromise was still held sacred. Finally, however, it was with Douglas's assistance that the Compromise measures of 1850 were passed, one of which provided for territorial Governments for Utah and New Mexico with the proviso that, when admitted as States, slavery should be