 Kuedza kweGermany kushandisa ngarava dzavo dzepasi pemvura U-boats kuvhara Britain kwakaguma norufu rwavafambi navafambisi vengarava vokuAmerica, uye kurwiswa kwezvikepe zvinotakura vanhu kwakaparira kutsamwa kwevanhu. Chinokosha zvikurusa chakanga chiri kuparadza pasina nyevero chikepe chevatakurwi chinonzi Lusitaniamuna 1915. Germany yakavimbisa kusadzokorora; zvisinei yakashandura nzvimbo mukutanga kwa1917, ichitenda kuti hondo isina muganho yeU-boat kurwisa ngarava dzose dzakananga kuBritain yaizokunda hondo, kunyange zvazvo pamutengo wekupinda kweAmerica. Apo vokuAmerica vakaverenga mashoko echiGermany okupa kuMexico, anozivikanwa seZimmermann Telegram, vakaona chipo chokuti Mexico iite hondo neGermany ichirwisa United States, ichitsigirwa nemari yeGermany, iine chipikirwa chokudzorerwa kwenzvimbo dzakarasika dzeArizona, New Mexico, uye Texas. Musi waApril 1, 1917, Wilson akadaidzira hondo, achisimbisa kuti U.S. yaifanira kurwisana kuti ichengete rukudzo rwayo uye kuva nenzwi rinogumisa mukuumba nyika itsva yapashure pehondo. Congress yakavhotera pana April 6, 1917 kuzivisa hondo, asi yakanga iri kure nokuva inobvumirana. 