9 4 1 , ▁he ▁returned ▁to ▁the ▁United ▁States ▁and ▁reported ▁for ▁duty ▁at ▁San ▁Diego ▁with ▁ 2 nd ▁Marine ▁Division ▁as ▁operations ▁officer . ▁Walker ▁has ▁been ▁promoted ▁to ▁the ▁rank ▁of ▁colon el ▁on ▁ 1 ▁January ▁ 1 9 4 2 ▁and ▁after ▁five ▁months ▁with ▁ 2 nd ▁Division , ▁he ▁was ▁appointed ▁command ing ▁officer ▁of ▁the ▁newly ▁activ ated ▁ 2 2 nd ▁Marine ▁Regiment ▁at ▁Camp ▁Elli ott , ▁California . ▁ ▁The ▁ 2 2 nd ▁Mar ines ▁were ▁sent ▁to ▁the ▁Pacific ▁the ater ▁and ▁subsequently ▁arrived ▁to ▁Sam oa ▁at ▁the ▁end ▁of ▁June . ▁Colonel ▁Walker ▁subsequently ▁commanded ▁the ▁regiment , ▁which ▁was ▁designated ▁as ▁independent ▁unit ▁during ▁the ▁island ▁defense ▁and ▁also ▁conducted ▁the ▁int ensive ▁j ung le ▁training . ▁Walker ▁did ▁not ▁see ▁combat ▁until ▁February ▁ 1 9 4 4 , ▁when ▁his ▁unit ▁participated ▁in ▁the ▁Battle ▁of ▁En iw et ok . ▁He ▁land ed ▁on ▁En geb i ▁Island ▁on ▁ 1 8 ▁February ▁following ▁the ▁Naval ▁bomb ard ment . ▁Walker ▁placed ▁his ▁command ▁post ▁on ▁the ▁beach ▁and ▁participated ▁in ▁the ▁hand - to - hand ▁fighting , ▁when ▁almost ▁one ▁thousand ▁of ▁Japanese ▁soldiers ▁were ▁killed ▁with ▁only ▁ 8 5 ▁dead ▁and ▁missing ▁plus ▁ 1 6 6 ▁wounded ▁US ▁soldiers . ▁On ▁ 2 2 ▁February , ▁Walker ▁and ▁his ▁ 2 2 nd ▁Mar ines ▁inv aded ▁the ▁Par ry ▁Island ▁and ▁continued ▁to ▁fight ▁the ▁enemy