States' rights
By 1863, two years into the war, Lincoln had changed the focus of the war to slavery and issued the Emancipation Proclamation. It made freeing the slaves a goal of the Civil War. It also weakened Confederate efforts to get help from the United Kingdom and France, which had thought about officially recognizing the Confederacy. As Union troops advanced into Confederate territory, they freed thousands of slaves per day. Manyof them did not wait for the troops but fled their owners to claim their freedom. Five slave states, called the border states, had remained loyal to the Union and were not at war with the federal government. Thus, Lincoln did not have authority to free slaves in those states and so the Proclamation was not applied to those states. The Proclamation also did not apply to Tennessee and to areas within Virginia and Louisiana that Union forces already controlled.