Lincoln justified the emancipation proclamation on grounds of?

Lincoln justified the Emancipation Proclamation primarily on the grounds of military necessity and the preservation of the Union. He viewed the abolition of slavery as a strategic measure to weaken the Confederacy, as it deprived them of labor and resources. Additionally, he framed the proclamation as a moral imperative, aligning the Union’s war efforts with the principles of freedom and human rights. Ultimately, it aimed to redefine the Civil War's purpose, making it not just a fight to preserve the nation, but also a struggle for liberty.