The debate on this subject commenced in the Senate. In the course of January and February, 1820, Rufus King, senator from New York, delivered two of the most well-considered and powerful speeches that this Missouri question elicited. The remarks they drew forth from Mr. Adams render it proper that some idea of their general course should be stated, although it is impossible that any abstract can do justice to them. Disclaiming all intention to encourage or assent to any measure that would affect the security of property in slaves, or tend to disturb the political adjustment which the constitution had established concerning them, he enters at large into the power of Congress to make and determine whatever regulations are needful concerning the territories. He maintained that the power of admitting new states is by the constitution referred wholly to the discretion of Congress; that the citizens of the several states have rights and duties, differing from each other in the respective states; that those concerning slavery are the most remarkable--it being permitted in some states, and prohibited in others; that the question concerning slavery in the old states is already settled. Congress had no power to interfere with or change whatever has been thus settled. The slave states are free to continue or abolish slavery. The constitution contains no provision concerning slavery in a new state; Congress, therefore, may make it a condition of the admission of a new state that slavery shall forever be prohibited within it. Mr. King then enters upon the history of the United States relative to this subject, and to the rights of the citizens of Missouri resulting from the terms of the cession of Louisiana, and of the act admitting it into the Union. From this recapitulation and illustration he demonstrates, beyond refutation, that Congress possesses the power to exclude slavery from Missouri. The only question now remaining was to show that it ought to exclude it. In discussing this point, Mr. King passes over in silence arguments which to some might appear decisive, but the use of which in the Senate of the United States would call up feelings that he apprehended might disturb or defeat the impartial consideration of the subject.