I put aside, also, the argument of the Senator from Pennsylvania [Mr. COWAN], so carefully and elaborately stated, to the effect that on the 1st of March, when the disloyal letter was written, there was no war actually existing between the Rebel States and the United States. Even if this assumption were correct, even if the United States were still hesitating what course to adopt, nothing is clearer than this: the Rebel States were in rebellion,--organized, armed, and offensive,--with the avowed purpose of overthrowing the National Government within their borders; and such rebellion was, beyond all question, a levying of war under the Constitution of the United States, so that all adherence to it, giving aid and comfort, was treason itself. But even if not disposed to admit actual levying of war on the part of the Rebels,--though of this there can be no doubt,--there was surely preparation and purpose so to do; and any contribution to such preparation and purpose was disloyalty, if not treason. Clearly, Jefferson Davis at that time was a traitor, at the head of traitors. What, then, can be thought of a Senator who offered arms to him? I put aside, also, the suggestion of the Senator from New Jersey [Mr. TEN EYCK], founded on the language of the President in his inaugural address of the 4th of March. It is true that the President spoke of the Rebels in generous, fraternal words, such as became the Chief Magistrate of a great people, not yet renouncing the idea of conquering by kindness, and not forgetting that Leviathan was tamed by a cord. But, whatever the language of the President, it is none the less clear that the Rebellion at that very moment was completely organized by a succession of overt acts, which fixed the treasonable position of its authors, and especially of its chief, to whom the letter offering arms was addressed. I put aside, also, the argument of the Senator from California [Mr. LATHAM], especially that part founded on the tolerance shown to treason, when uttered here by the retiring Rebels. Nobody questions that treason was uttered on this floor, or that treasonable counsels went forth from this Chamber. But the Senate was then controlled by the associates of the Senator of Indiana, and it was not in our power to check or chastise the traitors. It is within the recollection of many that those utterances were heard on this side of the Chamber, not only with indignant patriotism, but with bitter, stinging regret at the abject condition of the Senate, then so entirely in the hands of traitors that we were obliged to hear in silence. Surely such utterances, wicked with treason, constituting the very voice of the Rebellion, cannot be an apology for the disloyal letter of the Senator; nor can silence, when we were powerless to act, be any argument for silence now that power and responsibility are ours.