The American Expeditionary Force took over trenches from the French Army, so they did not have to dig any major positions when they entered into the Allied line.

However, by the time that the AEF was beginning to play more than a tactical role in the fighting, so by about July/August 1918, static trench lines had essentially become obsolete. Since fall, 1916 at least, Franco-British forces had honed the means to break into German positions at will, while since the beginning of 1917 the Germans had moved away from static trench lines towards a form of elastic defense in depth, making use of pillboxes and obstacle zones backed by infantry counter-attacks to defend ground. The fighting had moved away from static positional warfare in 1917, and the transition to mobile maneuver warfare had already taken place by summer 1918.