In July of 1864, the Civil War was in its fourth summer, its end point uncertain but its enormous cost in human life painfully clear. The Union Army had not yet achieved the decisive victory that would insure the vindication of Lincoln’s understanding of the Union as unbreakable. And the people of the North were questioning the war’s human cost. Looking ahead to the fall presidential election, Lincoln thought it unlikely that voters would return him to office, and he expected that his Democratic opponent, if elected, would begin negotiating peace on Confederate terms–probably allowing slavery to continue and implicitly or explicitly acknowledging the right of individual states to nullify federal law or withdraw from the Union at will.
Hence we can infer that a bill pushed through Congress by radical Republicans just before it adjourned for summer recess seemed to Lincoln intemperate and impractical. The Wade-Davis bill tried to predetermine the policy for the reconstruction of the South that would follow a Union victory in the war. It would have stipulated that only those who could swear an oath that they had never given aid to the Confederacy be allowed to vote in the reconstructed states. It would also have required any state readmitted to the Union to have abolished slavery. Lincoln had shown through the Emancipation Proclamation that he now saw the abolition of slavery as a necessary outcome of the war, but he wanted that abolition to be made permanent by Constitutional amendment, and securing the two-thirds majority necessary to pass the Thirteenth Amendment through the House of Representatives was proving difficult. Lincoln pocket-vetoed the Wade-Davis bill, but he went on to issue on July 8 a proclamation explaining this action, in which he said he was
unprepared, by a formal approval of this Bill, to be inflexibly committed to any single plan of restoration; and . . . I am also unprepared to declare, that the free-state constitutions and governments, already adopted and installed in Arkansas and Louisiana, shall be set aside and held for nought, thereby repelling and discouraging the loyal citizens who have set up the same, as to further effort; or to declare a constitutional competency in Congress to abolish slavery in States, but am at the same sincerely hoping and expecting that a constitutional amendment, abolishing slavery throughout the nation, may be adopted . . . .
On July 18, Lincoln issued a letter evidently intended for the Confederate leadership but refraining from addressing them as such, lest he imply their political legitimacy. Instead, he advised those “To Whom It May Concern” that he would entertain and consider “Any proposition which embraces the restoration of peace, the integrity of the whole Union, and the abandonment of slavery, and which comes by and with an authority that can control the armies now at war against the United States.”