of the monies herein appropriated, neither slavery nor involuntary servitude shall ever exist in any part of said territory, except for crime, whereof the party shall be duly convicted.”
With this amendment, commonly known as the Wilmot Proviso, the bill passed the House, but was lost in the Senate on account of the Proviso. Thus the President was left without any means to negotiate a treaty by which much suffering and many thousand precious lives might have been spared. But this would have thwarted the very design which had occasioned the war—the acquisition of more territory for slavery.
It was about this time that the doctrine of Popular Sovereignty was advanced. First conceived in the brain of Calhoun, it was first enunciated by General Cass when about to be used by the Democratic party as a candidate for the Presidency. The great argument, prior possession, against prohibiting slavery from the territories heretofore urged, had now failed, for the condition of territory was exactly reversed from what it had been formerly. This territory had never been polluted by slavery. But, to meet the exigency of the situation, a new dogma is brought forward that Congress has no right to prevent the citizens of the United States from taking with them their property (slaves) into the territories and determining there their local institutions for themselves. This doctrine, so new and strange to the Democratic party, was not popular at first, for their Baltimore convention which nominated Cass for President, voted it out of their platform by an overwhelming majority.
After the peace with Mexico an attempt was made in the 30th Congress to organize the territories acquired from this Power and submit the question of slavery to the adjudication of the Supreme Court, its pulse having been previously felt upon the constitutionality of Popular Sovereignty. This bill passed the Senate, but was killed in the House by a motion of Alexander H. Stephens, of Georgia. Various attempts were made in the 29th and 30th Congresses to organize the territories
