In Congress, during the past month, debate has turned mainly on topics connected with the approaching Presidential contest. In the Senate, the resolutions upon the subject of non-intervention have been still further discussed, but no vote has been taken upon them. On the 18th of March, Senator Jones, of Tennessee, replied at length to the speeches of Senators Cass and Seward upon this subject--seeking to establish, by copious citation of authorities, that it had never been the policy of this country to take any part whatever in the affairs of other nations, and urging the importance of still adhering to this course. He was opposed to protesting against the violation of international law by Russia, unless we were prepared to enforce that protest by war. Senator Cass rejoined, defending his positions from the assault of Senator Jones. On the 22d, Senator Soulé, of Louisiana, spoke upon the subject. Whatever might be the fate of the resolutions, he said, their discussion had given the country a chance of expressing its sympathy with the oppressed and down-trodden nations of the earth. He then entered upon a historical argument of some length to show that the neutrality advocated and enforced by Washington, during the war between England and France, was simply a matter of necessity--a temporary measure, which the exigencies of the time demanded; and that it was not regarded by Washington as a permanent rule for the action of this country. And further, even if this were not so, and if Washington had really set forth the doctrine, that this country must always remain indifferent to the movements of other nations, Senator Soulé urged, our national growth and progress would render it obsolete. The policy of this nation could not remain the same from century to century; it must change with changing circumstances, and keep pace with the rapid increase of our national population and power. Upon the conclusion of his remarks, the subject was again postponed. On the 26th, a message from the President announced that certain papers, connected with the prosecution of Mexican claims, which had been placed on file in the State Department, had been abstracted therefrom; and asking for the adoption of measures for the better protection of public documents and papers. On the 19th, Senator Cass made a statement of his views on the Wilmot Proviso, in reply to some remarks in a published letter from Senator Davis, of Mississippi. He denied the right of Congress to impose upon a territorial government any restriction in regard to its legislation upon slavery, claiming for the Legislature the right to establish or prohibit slavery, as it may see fit. He also justified the first settlers of California in the steps they took for the establishment of a government, and complained that many gentlemen at the South did not make a just and proper allowance for the sentiments of the North concerning slavery. In the _House of