page_title: Operation Cobra
section_title: Planning
hierarchical_section_title: Operation Cobra / Planning
context_page_description: Operation Cobra was the codename for an offensive launched by the United States First Army under Lieutenant General Omar Bradley seven weeks after the D-Day landings, during the Normandy campaign of World War II. The intention was to take advantage of the distraction of the Germans by the British and Canadian attacks around Caen in Operation Goodwood, and thereby break through the German defenses that were penning in their forces while the Germans were unbalanced. Once a corridor had been created, the First Army would then be able to advance into Brittany, rolling up the German flanks once free of the constraints of the bocage country. After a slow start, the offensive gathered momentum and German resistance collapsed as scattered remnants of broken units fought to escape to the Seine. Lacking the resources to cope with the situation, the German response was ineffectual and the entire Normandy front soon collapsed. Operation Cobra, together with concurrent offensives by the British Second Army and the Canadian First Army, was decisive in securing an Allied victory in the Normandy campaign.
context_section_description: The originator of the idea for Operation Cobra is disputed. According to Montgomery's official biographer, the foundation of Operation Cobra was laid on 13 June. Planning was immensely aided by detailed Ultra intelligence which supplied up-to-date decodes of communications between Oberkommando der Wehrmacht (OKW, the German armed forces high command) and Hitler's generals. Montgomery's plan at that time called for the U.S. First Army to take Saint-Lô and Coutances and then make two southward thrusts; one from Caumont toward Vire and Mortain and the other from Saint-Lô toward Villedieu and Avranches. Although pressure was to be kept up along the Cotentin Peninsula towards La Haye-du-Puits and Valognes, the capture of Cherbourg was not the priority. With the capture of Cherbourg by VII Corps on 27 June, Montgomery's initial timetable was overtaken by events and the thrust from Caumont was never adopted.
  Following the conclusion of Operation Charnwood and the cancellation of the First Army offensive towards Saint-Lô, Montgomery met with Bradley and Dempsey on 10 July to discuss plans for the 21st Army Group. Bradley said that progress on the western flank was very slow but that plans had been laid for another breakout attempt, codenamed Operation Cobra, to be launched by the First Army on 18 July. Montgomery approved the plan and that the strategy would remain the diversion of German attention from the First Army to the British and Canadian sector. Dempsey was instructed to "go on hitting, drawing the German strength, especially the armour, onto yourself—so as to ease the way for Brad". To accomplish this, Operation Goodwood was planned and Eisenhower ensured that both operations would have the support of the Allied strategic bombers.
  On 12 July, Bradley briefed his commanders on the Cobra plan, which consisted of three phases. The main effort would be under the control of VII Corps. In the first phase, the breakthrough attack would be conducted by the 9th Infantry Division (Major General Manton S. Eddy) and the 30th Infantry Division (Major General Leland Hobbs), which would break into the German defensive zone and then hold the flanks of the penetration while the 1st Infantry Division (Major General Clarence Huebner) and 2nd Armored Division (Major General Edward H. Brooks) pushed into the depth of the position until resistance collapsed. The 1st Infantry Division "was to take Marigny, with this objective exploited by a stream of General Watson's 3rd Armored Division armor that would move south toward Coutances". The 2nd Armored Division—part of "Collins' exploitation force" of the 2nd Armored Division in the east of the VII Corps sector and the "1st Infantry Division reinforced by Combat Command B (CCB) of the 3rd Armored division in the west"—would "pass through the 30th Infantry Division sector ... and guard the overall American left flank." If VII Corps succeeded, the western German position would become untenable, permitting a relatively easy advance to the southwest end of the bocage to cut off and seize the Brittany peninsula. First Army intelligence estimated that no German counterattack would occur in the first few days after Cobra's launch and that if they did later, they would be no more than battalion-sized operations.
  Cobra was to be a concentrated attack on a 6,400 m (7,000 yd) front, unlike previous U.S. broad front offensives and would have a mass of air support. Fighter-bombers would concentrate on hitting forward German defenses in a 230 m (250 yd) belt immediately south of the Saint-Lô–Periers road, while General Spaatz's heavy bombers would bomb to a depth of 2,300 m (2,500 yd) behind the German main line of resistance. It was anticipated that the physical destruction and shock value of a short, intense preliminary bombardment would greatly weaken the German defense so in addition to divisional artillery, Army- and Corps-level units would provide support, including nine heavy, five medium and seven light artillery battalions. More than a thousand divisional and corps artillery pieces were committed to 
caption: German dispositions, night of 24–25 July 1944
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