Study the timeline. The South fought south of the Potomac until Gettysburg. Gettysburg was a tactical move to get behind the union army, force it to surrender, and thus make the North leave the South the hell alone.
Had the Lincoln not wanted a war, there would have been no war. That is a simple, clear fact.
FIFY
What about the battle of Antietam?
OK, lets study the timeline.
Lee's invasion of Pennsylvania: - June/July 1863.
Lee's invasion of Maryland: September, 1862
Bragg's invasion of Kentucky: August, 1862
Polk invades Kentucky : September, 1861
Battle of Belmont Missouri: November, 1861
Battle of Boonville, Missouri: June, 1861
Battle of Cape Girardeau, Missouri: April, 1863
Battle of Carthage, Missouri: July, 1861
Battle of Glorieta Pass, New Mexico: March, 1862
Battle of Valverde, New Mexico: February, 1862