8 Infantry Division (USA) was to the west of the breakthrough sector
The 8th Infantry Division conducted an active defense along the Ay River, fixing the Germans to its front.
It also rotated subordinate units to rest and refit for the major breakthrough offensive, codenamed COBRA.
COBRA envisioned a massive “carpet bombing” 20 followed by three infantry divisions attacking to punch a hole in enemy lines, and then two armored divisions and a motorized infantry division exploiting through the hole thus made.
As the gap widened and resistance crumpled, further forces would pour through or follow up in pursuit.
The 8th Infantry Division was to the west of the breakthrough sector, and was to attack to fix and then hopefully overwhelm the forces to its immediate front as divisions coming through the gap penetrated deep into their rear.
COBRA was set for 21 July, but was postponed to 22, 24 and then 25 July because of weather.
On the morning of 25 July more than 2,400 Allied planes dropped more than 4,000 tons of bombs within sixsquare- mile sector of the German front west of Saint-Lô.