At the start of the Civil War, most Union soldiers were fighting to keep the United States together. The Southern states had seceded, thus splitting the United States apart, and war was now the only way to prevent secession from becoming a permanent condition. The integrity of the United States...
At the start of the Civil War, most Union soldiers were fighting to keep the United States together. The Southern states had seceded, thus splitting the United States apart, and war was now the only way to prevent secession from becoming a permanent condition. The integrity of the United States was now at stake, and most Union soldiers joined up in the belief that they were fighting to preserve that integrity.
It's unlikely that this initial motivation changed all that much during the Civil War. Some soldiers will doubtless have been inspired by President Lincoln's stirring words in the Gettysburg Address, where he talked of a "new birth of freedom." But the vast majority will still have seen their role not so much as bringing about the end of slavery, but as putting down a treacherous secession that threatened the long-term integrity of the United States.
The motivations of Confederate soldiers were more mixed. Some believed it was their duty to defend their individual states. This was the main motivation behind General Lee's decision to stand with his home state of Virginia after it voted for secession. Others, however, had a more general commitment to the principle of states' rights, which they saw as being under threat from the recent election of Abraham Lincoln as president.
Still others will have fought to defend the institution of slavery. Though the vast majority of Confederate soldiers didn't own any slaves, they still understood that slavery underpinned the entire Southern economy and society—indeed, the whole Southern way of life.
As the Union army made deeper and deeper incursions into Confederate territory, Southern soldiers were mainly concerned with defending their homeland against what they saw as a foreign invader. The Confederacy was effectively a different country, so its troops believed that they were doing their patriotic duty in resisting Union forces.