These Defense Battalions provided the first combined arms teams and proved to be a very effective fighting force.

Defense Battalions were among the first to embrace the "detachment concept" and task organize as required for the mission on each island.

Despite their extraordinary development, the first Defense Battalions suffered from insufficient manpower and equipment to properly execute counterattacks.

Consequently, every Marine in a Defense Battalion also trained to fight as an infantryman.

The transition to a more offensive employment method forced the Defense Battalions to adapt, leading to tremendous growth in strength, weaponry, and capabilities.

Rudder had enlisted in 1943 and served with the 51st Defense Battalion.

His first duty assignment was as a battery officer with the 18th Defense Battalion at Camp Lejeune.

Assigned to the 6th and 7th Defense Battalions, he reached the rank of Corporal before he was discharged.

In addition, 20 Defense Battalions were also set up, as well as a Parachute Battalion.

There, they met with additional ships which sailed with their supplies as well as the remaining elements of the brigade, the 5th Defense Battalion.