Why was Sherman's conquest of Atlanta important to the Union?

In the summer of 1864, during the U. S. Civil War (1861-65), Union General William T. Sherman faced off against Confederate generals Joseph E. Johnston and John B. Hood in a series of battles in northern Georgia. Sherman's goal was to destroy the Army of the Tennessee, capture Atlanta and cut off vital Confederate supply lines. While Sherman failed to destroy his enemy, he was able to force the surrender of Atlanta in September 1864, boosting Northern morale and greatly improving President Abraham Lincoln's re-election bid. With Atlanta under Union control, Sherman embarked on his March to the Sea, which laid waste to the countryside and hastened the Confederacy's defeat.