Lincoln ended his letter by appealing to anti-slavery supporters and hinted that action may be forthcoming if necessary, writing that he shall do more or less if he believes it will help save the Union. Finally, he made a distinction between his view of “official duty” as president and his “oft-expressed personal wish that all men everywhere could be free,” reminding the public that he had consistently advocated for the ultimate extinction of slavery.
Even though Greeley, anti-slavery Republicans, and abolitionists might not be completely satisfied by Lincoln’s letter, he knew their attitudes would change once he announced the proclamation, because it would be far more sweeping than the Second Confiscation Act could ever have been. Lincoln believed that only the president as the commander-in-chief could exercise war powers to free slaves in states in rebellion. At the same time, the president needed to frame his policy as being dedicated to preserving the Union above all, in a way that would be acceptable to the border states and his fragile Union coalition, in order to avoid negatively impacting vulnerable Republicans ahead of the upcoming midterm elections in the fall.
Of course, they want everyone to ignore All The Facts.