Final answer:
Lincoln's advisors initially resisted the Emancipation Proclamation due to concerns about public perception, legality, diplomacy, and the economy. Lincoln later saw it as essential for military strategy and as a means to redefine the objectives of the Civil War, resulting in its issuance in 1863.
Step-by-step explanation:
Initially, Lincoln's advisors did not support the issuance of the Emancipation Proclamation for several reasons, including concerns over its reception by the public, doubts about its legal authority, fears of worsening diplomatic relations, and potential harm to the economy. However, as the Civil War progressed, Lincoln viewed emancipation as a military necessity and a strategy to undermine the Confederate war effort by freeing slaves, thereby crippling the South's ability to fight.
The Emancipation Proclamation, after its announcement in 1862 and effectuation on January 1, 1863, refocused the war aims towards the abolition of slavery and opened paths for the inclusion of African Americans as soldiers in the Union army, despite the mixed reactions it received in different regions and among various groups.