text: Chapter 2
  Rapid Task Organization: 30th Infantry Division in the Normandy
  Campaign
  From June to October of 1944 in the European theater of operations in the Second
  World War, the U.S. Army executed 9 changes in corps alignment under field armies
  and more than 65 changes of division alignment under corps commands. This required
  corps, divisions, brigades, and battalions to execute task organization changes rapidly,
  often while in contact with the enemy, to provide maximum flexibility and options to
  higher commands. By making organizational transitions a routine action, the Allies
  were able to converge and mass combat power at decisive points to achieve the
  objectives of the Normandy invasion, break through the German defenses, and
  advance into the French interior.
  The wartime experience of the 30th Infantry Division and its 14,000 Soldiers illustrated
  the opportunities and challenges created by rapid and continuous changes to task
  organization. On 11 June, “Old Hickory” joined the war with an uncontested landing on
  the Normandy beaches under command of the VII Corps. Less than a week later, it
  reported to XIX Corps to execute its first combat action with one regiment even as the
  rest of its forces came ashore. The division, when fully consolidated, next defended
  the vulnerable lines between American beachheads to allow the Allies to mass combat
  power and then subsequently the division attacked across the Vire River to repel a
  German counterattack.
  Beginning on 15 July, the 30th Division served as a lead element in Operation Cobra
  as the Allies broke through the German defenses surrounding Normandy. The division
  initially secured the departure point for the entire Allied operation, then executed a
  mid-night reassignment to VII Corps, and finally resumed its advance the next morning.
  Seeking to exploit success, the command transferred back to XIX Corps to repel a
  German counterattack, moved to the V Corps, and then rejoined XIX Corps to repulse
  a major counterattack at Avranches. This flexibility in changing task organization
  ultimately allowed field commanders to continuously mass and reallocate combat
  power at decisive points in the campaign.
  Command and Support Relationships
  2-67. Establishing clear command and support relationships is the basis for establishing an effective task
  organization. These relationships establish responsibilities and authorities between subordinate and
  supporting units. Some command and support relationships limit the commander’s authority to prescribe
  additional relationships. Knowing the inherent responsibilities of each command and support relationship
  allows commanders to effectively organize their forces and helps supporting commanders understand their
  unit’s role in the organizational structure.
  2-68. Army echelons above brigade commanders and staffs must clearly understand joint command
  relationships and authorities as well as Army command and support relationships. Differences stem from the
  way Army forces task-organize internally and the need for a system of support relationships between Army
  forces. Another important difference is the requirement for Army commanders to handle the ADCON of
  forces. These differences allow for flexible allocation of Army capabilities within various Army echelons.
  Army command and support relationships are the basis for building Army task organizations. (See Chapter
  5Appendix A for a detailed description of command and support relationships.)
  Span of Control
  2-69. Span of control is an important consideration when task-organizing the force. Span of control refers to
  the number of subordinates or activities under the control of a single commander. A commander’s span of