46. The Battle of Antietam was an important Union victory because A. Confederate forces had attacked Union territory, and their defeat greatly increased morale in the North B. Union forces secured a quick and easy victory against the Confederates without much loss of life on either side C. Confederate General Stonewall Jackson was hit by friendly fire and could no longer lead his troops against the Union D. General McClellan's Union forces pursued the retreating Confederates and destroyed their ability to advance into the North again