ac ru z ▁and ▁T amp ico ▁in ▁ 1 9 1 7 – 1 9 1 8 , ▁so ▁as ▁to ▁pac ify ▁the ▁Te hu ante pec ▁Ist hm us ▁and ▁T amp ico ▁oil ▁fields ▁and ▁ensure ▁their ▁continued ▁production ▁during ▁the ▁civil ▁war , ▁but ▁this ▁time ▁the ▁relatively ▁new ▁Mexican ▁President ▁Ven ust iano ▁Car ran za ▁threatened ▁to ▁destroy ▁the ▁oil ▁fields ▁in ▁the ▁event ▁that ▁the ▁Mar ines ▁land ed ▁there . ▁ ▁Japanese ▁response ▁The ▁government ▁of ▁Japan , ▁another ▁nation ▁mentioned ▁in ▁the ▁Z imm erman ▁Tele gram , ▁was ▁already ▁involved ▁in ▁World ▁War ▁I , ▁on ▁the ▁side ▁of ▁the ▁Al lied ▁Pow ers ▁against ▁Germany . ▁The ▁Japanese ▁government ▁later ▁released ▁a ▁statement ▁that ▁Japan ▁was ▁not ▁interested ▁in ▁changing ▁sides ▁and ▁attack ing ▁America . ▁ ▁Aut ograph ▁discovery ▁In ▁October ▁ 2 0 0 5 , ▁it ▁was ▁reported ▁that ▁an ▁original ▁typescript ▁of ▁the ▁dec oded ▁Z imm ermann ▁Tele gram ▁had ▁recently ▁been ▁discovered ▁by ▁an ▁un named ▁historian ▁who ▁was ▁research ing ▁and ▁prepar ing ▁an ▁official ▁history ▁of ▁the ▁United ▁Kingdom ' s ▁Government ▁Communic ations ▁Head quarters ▁( G CH Q ). ▁The ▁document ▁is ▁believed ▁to ▁be ▁the ▁actual ▁tele gram ▁shown ▁to ▁the ▁American ▁amb assador ▁in ▁London ▁in ▁ 1 9 1 7 . ▁Mark ed ▁in ▁Admir al ▁Hall ' s ▁hand writing ▁at ▁the ▁top ▁of ▁the ▁document ▁are ▁the ▁words : ▁" This ▁is ▁the ▁one ▁handed ▁to