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.

Between these extremes were grouped the followers of Senator Cass of
Michigan, who was perhaps the most conspicuous candidate for the
Democratic nomination. In his famous Nicholson letter of December 24,
1847, he questioned both the expediency and constitutionality of the
Wilmot Proviso. It seemed to him wiser to confine the authority of the
general government to the erection of proper governments for the new
countries, leaving the inhabitants meantime to regulate their internal
concerns in their own way. In all probability neither California nor
New Mexico would be adapted to slave labor, because of physical and
climatic conditions. Dickinson of New York carried this doctrine,