[USMCRET6391]

Marine Corps Airborne Doctrine

On 15 May 1940 the Commandant, Major General Thomas Holcomb, wrote the Chief of Naval Operations to seek the help of his naval attaches in gathering information on foreign parachute programs. He noted that he was "intensely interested" in the subject. The Berlin attache responded the following month with a lead on how to obtain newsreels and an educational film on the German paratroopers. The London attache eventually provided additional information on the Germans and on Britain's fledgling parachute program launched in June 1940.

The Commandant's own intelligence section had already compiled available material on the German and Soviet forces. The report noted the distinction between parachutists and air infantry, the latter consisting of specially organized units trained and equipped to move by transport aircraft. The paratroopers acted as the advance guard for the air infantry by seizing the airfields upon which the transports would land. The report also detailed the different methods that the Germans and Soviets used to train their respective forces. German paratrooper recruits went through an intensive ground school prior to making the six jumps required to achieve membership in a unit. The Soviet program featured the use of towers for practice jumps prior to actual training with a plane. When staff officers at Headquarters first looked at parachute forces in the aftermath of Eben Emael, they specifically considered the functions such a unit would perform. Their ideas were generally similar: paratroopers would be valuable for raids, reconnaissance, the seizure of airfields, aerial envelopment of the enemy's rear area, and the occupation of key terrain in advance of the main force. Several officers specifically tied the latter two missions to the conduct of amphibious operations.

Although the Corps' amphibious doctrine had existed on paper for several years, the Fleet Marine Force was having a difficult time turning those ideas into reality. During annual exercises, a lack of decent landing craft and transports had prevented the rapid buildup ashore of combat power, something the amphibious force had to do if it hoped to defeat counterattacks against its beachhead. Brigadier General Holland M. Smith, commander of the 1st Marine Brigade, first tried to solve this problem during Fleet Exercise 6 in February 1940. A key part of his plan was the night landing of one company three hours prior to the main amphibious assault. This company, embarked in a fast destroyer transport, would go ashore by rubber boat, seize key terrain overlooking the proposed beachhead, and then protect the rest of the force as it landed and got itself organized. This idea eventually gave birth to the 1st Marine Raider Battalion. In the spring of 1940, it was obvious to a number of Marine officers, at Headquarters and in the PMF, that parachutists now constituted an ideal alternative for speedily seizing a surprise lodgement on an enemy coast. Smith explicitly would advocate that new wrinkle to doctrine the following year.

The Marine Corps did not develop formal airborne doctrine until late 1942. It came in the form of a 12-page manual titled Parachute and Air Troops. Its authors believed that airborne forces could constitute "a paralyzing application of power in the initial phase of a landing attack." Secondarily, parachute troops could seize "critical points," such as airfields or bridges, or they could operate behind enemy lines in small groups to gather intelligence or conduct sabotage operations. The doctrine noted the limitations of airborne assault and emphasized that these forces could only seize small objectives and hold them for a short time pending linkup with seaborne or overland echelons. The manual envisioned the formation of an air brigade composed of one regiment each of paratroops and air infantry, the type of force originally sought by Holland Smith.

The doctrinal publication did not provide much detail on tactics, but the parachutists worked out techniques in combination with Marine transport pilots. The standard of operations called for a terrain-hugging approach flight at altitudes as low as 50 feet, with a last-minute ascent to several hundred feet, at which point the jumpers exited the aircraft. All leaders were thoroughly briefed beforehand with maps, aerial photos, and a sandtable mockup of the objective, so that they could quickly get organized and oriented once they hit the ground. When they jumped, the paratroopers carried the collapsible Johnson weapons or Reisings, along with basic individual items such as a belt, knife, canteens, and ammunition. Cargo parachutes delivered heavier weapons and supplies.

From early in the life of the program, planners realized that a lack of training facilities and planes hampered the ability of the Corps to field an adequate airborne force. They thus began looking at using parachutists for secondary missions. In April 1941 the Commandant directed that parachute units conduct training in rubber boat operations, reconnaissance, demolitions, and other subjects to enable them to conduct special missions requiring only small forces or not necessarily involving airborne insertion. On New Caledonia in 1943, the 1st Parachute Regiment devoted much of its training time to such skills. In many respects the Marine Corps had molded the parachutists and raiders into carbon copies of each other, with the parachutists' unique ability to enter battle being the only significant difference between the two special units.