 Pashure pokupinda kweGermany muPoland, fariro huru yaRoosevelt navakuru vakuru vake vehondo yakanga iri pahondo muEurope, asi Japan yakaratidzirawo denho dzomutemo wokunze. Ukama neJapan hwakanga hwava kuramba huchiipa kubvira pakapinda kwayo muManchuriamuna 1931, uye akanga awedzera kuipa nokutsigira China kwaRoosevelt. Nehondo muEurope ichipinza ngwariro yamasimba makuru echikoloni, vatungamiriri veJapan vakatarira makoroni anotambura akadai seDutch East Indies, French Indochina, uye British Malaya. Pashure pokunge Roosevelt azivisa chikwereti chemamirioni 100 chakaenzana nebhirioni rimwe remadhora muna 2005 kuChina somuuyo wokupinda kweJapan kuchamhembe kweFrench Indochina, Japan yakasaina Chibvumirano cheTripartite neGermany neItaly. Chibvumirano chacho chakasunga nyika imwe neimwe kudzivirira dzimwe pakurwiswa, uye Germany, Japan, neItaly zvakava zvinozivikanwa samasimba eAxis. Ichikunda avo vaida kupinda muSoviet Union, vakuru vakuru veuto reJapan vakabudirira kutsigira kukunda kweSoutheast Asia kuti vave nechokwadi chokuramba vachiwana zvinhu zvakasvibirira. Muna July 1941, pashure pokunge Japan yatora chikamu chakanga chasara cheFrench Indochina, Roosevelt akagura kutengeswa kwamafuta kuJapan, achibvisira Japan inopfuura 95 muzana yezvinhu zvayo zvinogovera mafuta. Akaisawo uto rePhilippines pasi pokutonga kweAmerica uye akadzorera General Douglas MacArthur kubasa kuti atungamirire mauto eU.S. muPhilippines. 