id ▁and ▁the ▁Batt les ▁of ▁Cor al ▁Sea ▁and ▁Mid way . ▁It ▁was ▁sub mar ines ▁that ▁imm obil ized ▁the ▁Imperial ▁Japanese ▁Navy ' s ▁heavy ▁ships ▁and ▁brought ▁Japan ' s ▁economy ▁to ▁a ▁virtual ▁stand st ill ▁by ▁cri pp ling ▁the ▁import ation ▁of ▁oil ▁and ▁raw ▁materials : ▁by ▁the ▁end ▁of ▁ 1 9 4 2 , ▁the ▁amount ▁of ▁raw ▁materials ▁brought ▁in ▁was ▁cut ▁in ▁half , ▁" to ▁a ▁dis astr ous ▁ten ▁million ▁tons ", ▁while ▁oil ▁" was ▁almost ▁completely ▁stopped ". ▁Last ly , ▁the ▁bas ement ▁of ▁the ▁Old ▁Administration ▁Building ▁was ▁the ▁home ▁of ▁the ▁crypt anal yt ic ▁unit ▁which ▁contributed ▁significantly ▁to ▁the ▁Mid way ▁amb ush ▁and ▁the ▁Sub marine ▁Force ' s ▁success . ▁ ▁Ret ros pective ▁debate ▁on ▁American ▁intelligence ▁ ▁Ever ▁since ▁the ▁Japanese ▁attack , ▁there ▁has ▁been ▁debate ▁as ▁to ▁how ▁and ▁why ▁the ▁United ▁States ▁had ▁been ▁caught ▁una ware , ▁and ▁how ▁much ▁and ▁when ▁American ▁officials ▁knew ▁of ▁Japanese ▁plans ▁and ▁related ▁topics . ▁As ▁early ▁as ▁ 1 9 2 4 , ▁Chief ▁of ▁U . S . ▁Air ▁Service ▁Mason ▁Patrick ▁displayed ▁a ▁concern ▁for ▁military ▁vulner abilities ▁in ▁the ▁Pacific , ▁having ▁sent ▁Gen . ▁Billy ▁Mitchell ▁on ▁a ▁survey ▁of ▁the ▁Pacific ▁and ▁the ▁East . ▁Patrick ▁called ▁Mitchell ' s ▁subsequent ▁report , ▁which ▁identified ▁vulner abilities ▁in ▁Hawai i , ▁a ▁" the oret ical ▁treat ise ▁on ▁employ