Federalists, seeking to preserve Federal power and unity.
The emancipation proclamation only freed the slaves Lincoln and the Continental congress had no power over -- the slaves of their enemy.
It preserved ownership of the slaves, for their friends and allies.
Real motives exposed. Everything else is American myth used to justify the most costliest war in American history, in regards to lost American lives.
Very true. The Unites states was at risk of dissolving, and Lincoln wanted to embolden the slaves to revolt, kill their masters and hence destroy the south from within. Smart military strategy.
It was still legal to own slaves in the United States until passage of the 13th Amendment to the US Constitution in December of 1865.
"Now, therefore I Abraham Lincoln, President of the United States, by virtue of the power in me vested as Commander-in-Chief, of the Army and Navy of the United States in time of actual armed rebellion against the authority and government of the United States, and as a fit and necessary war measure for suppressing said rebellion, do, on this first day of January, in the year of our Lord one thousand eight hundred and sixty-three, and in accordance with my purpose so to do publicly proclaimed for the full period of one hundred days, from the day first above mentioned, order and designate as the States and parts of States wherein the the people thereof respectively, are on this day in rebellion against the United States, the following,to wit:
Arkansas, Texas, Louisiana (except the Parishes of St. Bernard, Plaquemines, Jefferson, St. John, St. Charles, St. James Ascension, Assumption, Terrebonne, Lafourche, St. mary, St. Martin, and Orleans, including the City of New Orleans), Mississippi, Alabama, Florida, Georgia, South Carolina, North Carolina, and Virginia, (except the forty-eight counties designated as West Virginia, and also the counties of Berkley, Accomac, Northampton, Elizabeth City, York, Princess Ann, and Norfolk, including the cities of Norfolk and Portsmouth), and which excepted parts, are for the present, left precisely as if this proclamation were not issued.
And by virtue of the power, and for the purpose aforesaid,
I do order and declare that all persons held as slaves within said designated States, and parts of States, are, and henceforward shall be free; and that the Executive government of the United States, including the military and naval authorities thereof, will recognize and maintain the freedom of said persons."
Abe Lincoln January 1, 1863
The Civil War started on April 12, 1861. About 2 years after the start of the war, Abe has a brainstorm, his proclomation. Why did he not free the slaves over the entire United states and territories?
Conclusion: Preserving the Union was the number 1 motive for the war.