Why did general Sherman conduct the devastating march to sea?

Answer 1

Because he did not think he would be able to pursue the Army of Tennessee into the mountains, with such a long and vulnerable supply-line.

Instead, he would turn Southeast, and conduct punitive raids across Georgia, living off the land as he went, so he would be able to forget his supply-line.

IMPROVEMENT

Sherman's March to the Sea can't be considered only as a series of punitive raids across Georgia. It was part of a major strategic plan aiming to take from behind the Confederacy's "Atlantic Fortress", approved by Grant and Lincoln.

It represented a new development of the Art of War. It was made possible by the error committed by the Confederates with their offensive against the Tennessee, which left no adequate force to keep at bay Sherman Army.

The European strategist would take eighty years to find out that penetrate in the heart of the enemy country can achieve more decisive outcomes than lagging against secondary objectives. The military leaders who applied the same principles

in the WW2 were Guderian, Cerniakowsky, Bradley, Patton, Rommel etc.