In President Lincoln's First Inaugural Address he stated that, "I have no purpose, directly or indirectly, to interfere with the institution of slavery in the States where it exists. I believe I have no lawful right to do so and I have no inclination to do so."
On April 15, 1861, Abraham Lincoln issued his famous proclamation for 75,000 militiamen to join the United States Army. Why? He stated it was to put down the insurrection and to "maintain the existence of our National Union."
In April of 1861, U.S. Secretary of State William Seward sent an official dispatch to the officers of foreign ministers of state in France and England declaring the official views and purposes of the United States government reason for going to war. In the official dispatch it said, among other official statements, "The condition of slavery in the several States will remain the same."
When the war began in April of 1861, the Union actually had MORE SLAVES than the Confederate States of America. In April of 1861, the Confederacy was made up of only 7 slaves states which included South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana and Texas. Had the United States government been fighting to end slavery it would have begun a fight against itself.
On July 4, 1861, in a special session of Congress, Lincoln formally declared that the purpose of the war was to preserve the Union. From the very founding of the country statesmen debated whether or not it was lawful to secede because "we the people" had made a federal compact which operated directly on the people and not upon the States. Lincoln took the side of the debate which would not allow any State to leave because it would destroy the unity and accumulated wealth of the nation.
On July 25, 1861, the 37th Congress (First Session) passed a bill, the Crittenden-Johnson Resolution which officially declared the purpose of the war to be that of preserving the Union with no intention "of overthrowing or interfering" with the insitution of slavery in its established form.
Lincoln and the Federal government had also hoped to gain the support of the border states of Delaware, Maryland, West Virginia, Kentucky and Missouri, all which were slave-holding states. At the onset of the war these states still depended on slave labor for economic stability, so the North would have lost any hoped-for support from these states if the War was truly fought for the purpose of ending slavery.
In his letter to the New York Tribune in 1862, President Lincoln wrote, "My paramount object in this struggle is to save the Union and is not either to save or destroy slavery."
On January 1, 1863, when the Southern States seemed to be winning the war for their independence, President Lincoln delivered his Emancipation Proclamation, which many Americans today believe "freed the slaves." However, this proclamation only freed the slaves which were in the territories of "rebellion." It did not free any slaves in states controlled by the Union. If the Union government had been, in truth, fighting a war to end slavery, why would its President not issue a proclamation to free ALL slaves in every state and territory? Why was it ONLY for the states "in rebellion"? People living at the time were shocked and surprised by Lincoln's proclamation because they had been told they were fighting and dying by the thousands to save the Union and now all of a sudden they were dying for the well-being of slaves in faraway states where most Northerners had never visited. In January of 1863, New York City dealt with race riots when angry white mobs assaulted black people. The proclamation also caused a desertion crisis in the Union army with over 200,000 Federal soldiers deserting, another 120,000 avoiding conscription and thousands fleeing to Canada. Historian James McPherson comments, "Plenty of soldiers believed the proclamation had changed the purpose of the war. They were willing to risk their lives for the Union, they said, but not for "black freedom.""
Europeans and Americans alike expressed feelings of shock and horror that the proclamation was just a war measure to incite a slave insurrection in those states to which it applied, thereby causing mass murder of the people left at home. Any hope for such an insurrection never took place because most of the people remaining at home while their men fought for independence behaved honorably.
In the end, the South lost its war for independence and the North succeeded in its stated cause of "preserving the Union."