In August 1943, he was named chief of staff of the 2nd Marine Division, which was then preparing for the invasion of Tarawa. He prepared an estimate of the situation for this operation which proved to be surprisingly accurate and has since become a classic in Marine Corps military literature. For this action, he received the Legion of Merit and was promoted to brigadier general (December 1, 1943). Later, he was appointed assistant division commander of the 2d Marine Division and participated in this capacity in the capture of Saipan and Tinian. The Silver Star was awarded him for these operations.