After the qualified Union victory in the Battle of Antietam, Lincoln issued a preliminary proclamation warning that in all states still in rebellion on January 1, 1863, he would declare their slaves “then, thenceforward, and forever free.” January 1 came, and with it the final proclamation, which committed the government and armed forces of the United States to liberate the slaves in rebel states “as an act of justice, warranted by the Constitution, upon military necessity.” The proclamation exempted the border slave states and all or parts of three Confederate states controlled by the Union army on the grounds that these areas were not in rebellion against the United States. Lincoln had tried earlier to persuade the border states to accept gradual emancipation, with compensation to slave owners from the federal government, but they had refused. The proclamation also authorized the recruitment of freed slaves and free blacks as Union soldiers; during the next 2 1/2 years 180,000 of them fought in the Union army and 10,000 in the navy, making a vital contribution to Union victory as well as their own freedom. Emancipation would vastly increase the stakes of the war. It became a war for “a new birth of freedom,” as Lincoln stated in the Gettysburg Address, a war that would transform Southern society by destroying its basic institution.