The report began with a constitutional argument in defense of the
Kansas-Nebraska Act. As a contribution to the development of the
doctrine of popular sovereignty, the opening paragraphs deserve more
than passing notice. The distinct advance in Douglas's thought
consisted in this: that he explicitly refused to derive the power to
organize Territories from that provision of the Constitution which
gave Congress "power to dispose of and make all needful rules and
regulations respecting the territory or other property belonging to
the United States." The word "territory" here was used in its
geographical sense to designate the public domain, not to indicate a
political community. Rather was the power to be derived from the
authority of Congress to adopt necessary and proper means to admit new
States into the Union. But beyond the necessary and proper
organization of a territorial government with reference to ultimate
statehood, Congress might not go. Clearly, then, Congress might not
impose conditions and restrictions upon a Territory which would
prevent its entering the Union on an equality with the other States.
From the formation of the Union, each State had been left free to
decide the question of slavery for itself. Congress, therefore, might
not decide the question for prospective States. Recognizing this, the
framers of the Kansas-Nebraska Act had relegated the discussion of the
slavery question to the people, who were to form a territorial
government under cover of the organic act.[551]

This was an ingenious argument. It was in accord with the utterances
of some of the weightiest intellects in our constitutional history.
But it was not in accord with precedent. There was hardly a
territorial act that had emerged from Douglas's committee room, which
had not imposed restrictions not binding on the older Commonwealths.