The relation of the war to the institution of slavery has been touched upon in describing several incidents which occurred during 1861, namely, the designation of fugitive slaves as "contraband," the Crittenden resolution and the confiscation act of the special session of Congress, the issuing and revocation of Fremont's proclamation, and various orders relating to contrabands in Union camps. The already mentioned resignation of Secretary Cameron had also grown out of a similar question. In the form in which it was first printed, his report as Secretary of War to the annual session of Congress which met on December 3, 1861, announced: "If it shall be found that the men who have been held by the rebels as slaves are capable of bearing arms and performing efficient military service, it is the right, and may become the duty, of the government to arm and equip them, and employ their services against the rebels, under proper military regulation, discipline, and command." The President was not prepared to permit a member of his cabinet, without his consent, to commit the administration to so radical a policy at that early date. He caused the advance copies of the document to be recalled and modified to the simple declaration that fugitive and abandoned slaves, being clearly an important military resource, should not be returned to rebel masters, but withheld from the enemy to be disposed of in future as Congress might deem best. Mr. Lincoln saw clearly enough what a serious political role the slavery question was likely to play during the continuance of the war. Replying to a letter from the Hon. George Bancroft, in which that accomplished historian predicted that posterity would not be satisfied with the results of the war unless it should effect an increase of the free States, the President wrote: "The main thought in the closing paragraph of your letter is one which does not escape my attention, and with which I must deal in all due caution, and with the best judgment I can bring to it." This caution was abundantly manifested in his annual message to Congress of December 3, 1861: "In considering the policy to be adopted for suppressing the insurrection," he wrote, "I have been anxious and careful that the inevitable conflict for this purpose shall not degenerate into a violent and remorseless revolutionary struggle. I have, therefore, in every case, thought it proper to keep the integrity of the Union prominent as the primary object of the contest on our part, leaving all questions which are not of vital military importance to the more deliberate action of the legislature.... The Union must be preserved; and hence all indispensable means must be employed. We should not be in haste to determine that radical and extreme measures, which may reach the loyal as well as the disloyal, are indispensable."