Mezue ahịrịokwu na-esonụ: N'ọnwa Machị afọ 1944, e kenyere Simpson ọrụ n'ụlọọrụ ndị agha nke atọ nke ndị agha mmiri ma sonye na
Ịkwada na Emirau, nke na-ezute enweghị iguzogide. E buliri ya n'ọkwa lieutenant colonel n'ọnwa Eprel 1944 ma nye ya iwu ka ọ laghachi na States otu ọnwa mgbe nke ahụ gasịrị. Mgbe ọ laghachiri na steeti ahụ, enyere Simpson iwu ka ọ gaa n'ụlọ akwụkwọ ndị agha na Command and Staff College na Fort Leavenworth, Kansas wee gụchaa na Nọvemba nke afọ ahụ.