During the Southern Campaign, the Americans mastered the Defense-in-Depth

A common tactic adopted by the Americans during the Southern Campaign came to be known as a defense in depth. The practice involved forming multiple lines of battle. Each successive position engaged the attacking force and then withdrew. Such a method was designed to delay an enemy's advance and inflict as many casualties as possible.

Morgan was the first to experiment with the concept, and he did so with great effect against a hand-picked British force under Banastre Tarleton at the Battle of Cowpens on January 17, 1781, thoroughly defeating Tarleton’s Legion and sending “Bloody Ban” flying in a wild panic. The engagement was a resounding American triumph. Tarleton was routed and lost 860 men of 1,100 engaged. Greene then adopted the tactic and applied it on a much larger scale at Guilford Courthouse on March 15. Even though he lost the battle, he scored a major strategic victory by punishing Cornwallis’ army and inflicting enormous losses on it for little gain—Greene’s army escaped to fight another day. His stand at Guilford Courthouse set the stage for the ultimate American victory at Yorktown.

There are many lessons to be learned from studying the development, implementation, and execution of the defense of depth at Cowpens and then again at Guilford Courthouse during the Southern Campaign.