DEAR SIR,--Never, except when suffering from positive disability, have I allowed myself to be absent from my seat in the Senate for a single day, and now, amid the extraordinary duties of the present session, I am more than ever bound by this inflexible rule. If anything could tempt me to depart from it, I should find apology in the invitation with which you honor me. The meeting called under such distinguished auspices is needed at this moment as a rally to those true principles by which alone this great Rebellion can be permanently suppressed. I should be truly happy to take part in it, and try to impart something of the strength of my own convictions. It is only necessary that people should see things as they are, and they will easily see how to deal with them. This is the obvious condition of practical action. Now, beyond all question, Slavery is the great original malefactor and omnipresent traitor,--more deadly to the Union than all Rebel leaders, civil or military. Therefore, as you are in earnest against the Rebellion, you will not spare Slavery. And happily the way is plain, so that it cannot be mistaken. Look throughout the whole Rebel territory, and you do not find a single officer legally qualified to discharge any function of Government. By the Constitution of the United States, “members of the several State Legislatures, and all executive and judicial officers, both of the United States and of the several States, shall be bound by oath or affirmation to support this Constitution.” But these functionaries have all renounced allegiance to the United States, and taken a new oath to support the Rebel Government, so that at this moment they cannot be recognized as constitutionally empowered to act. But a State is known only through its functionaries, constitutionally empowered to act; and since all these have ceased to exist, the State, with its unnatural institutions, has ceased to exist also, or it exists only in the lifeless parchments by which its Government was originally established. The action of these functionaries was impotent to transfer its territory to a pretended confederation. To destroy the State was all they could do. In the absence of any legitimate authority in this territory, Congress must assume the necessary jurisdiction. Not to do so is abandonment of urgent duty. Some propose a temporary military government; others propose a temporary provisional government, with limited powers. These all concede to Congress jurisdiction over the territory; nor can such jurisdiction be justly questioned. But I cannot doubt that it is better to follow the authoritative precedents of our history, and proceed as Congress is accustomed to proceed in the organization and government of other territories. This is simple.