When Douglas entered Washington in the fall of 1847, as junior Senator from Illinois, our troops had occupied the city of Mexico and negotiations for peace were well under way. Perplexing problems awaited Congress. President Polk sternly reminded the two Houses that peace must bring indemnity for the past and security for the future, and that the only indemnity which Mexico could offer would be a cession of territory. Unwittingly, he gave the signal for another bitter controversy, for in the state of public opinion at that moment, every accession of territory was bound to raise the question of the extension of slavery. The country was on the eve of another presidential election. Would the administration which had precipitated the war, prove itself equal to the legislative burdens imposed by that war? Could the party evolve a constructive programme and at the same time name a candidate that would win another victory at the polls? It soon transpired that the Democratic party was at loggerheads. Of all the factions, that headed by the South Carolina delegation possessed the greatest solidarity. Under the leadership of Calhoun, its attitude toward slavery in the Territories was already clearly stated in almost syllogistic form: the States are co-sovereigns in the Territories; the general government is only the agent of the co-sovereigns; therefore, the citizens of each State may settle in the Territories with whatever is recognized as property in their own State. The corollary of this doctrine was: Congress may not exclude slavery from the Territories. At the other pole of political thought, stood the supporters of the Wilmot Proviso, who had twice endeavored to attach a prohibition of slavery to all territory which should be acquired from Mexico, and who had retarded the organization of Oregon by insisting upon a similar concession to the principle of slavery-restriction in that Territory. Next to these Ultras were those who doubted the necessity of the Wilmot Proviso, believing that slavery was already prohibited in the new acquisitions by Mexican law. Yet not for an instant did they doubt the power of Congress to prohibit slavery in the Territories.