 Kuedza kweGermany kushandisa ngarava dzayo dzepasi pemvura U-boats kuvhara Britain kwakaguma norufu rwavafambi navafambisi vengarava vokuAmerica, uye kurwiswa kwezvikepe zvinotakura vanhu kwakaparira kutsamwa kwevanhu. Chinokosha zvikurusa chakanga chiri kuputirwa torpedo pasina nyevero kwechikepe chevatakurwi Lusitaniamuna 1915. Germany yakavimbisa kusadzokorora, asi yakashandura chimiro chayo mukuvamba kwa1917, ichidavira kuti hondo isina kuganhurirwa yeU-boat mukurwisana nezvikepe zvose zvaienda kuBritain zvaizokunda hondo kunyange pamutengo wokupinda 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. Pana April 1, 1917, Wilson akadaidzira hondo, achisimbisa kuti U.S. yaifanira kurwisa kuti ichengete rukudzo rwayo uye kuva nenzwi rinogumisa mukuumba nyika itsva yapashure pehondo. Congress yakavhotera pana April 6, 1917 kuzivisa hondo, 82 ku6 muSeneti, uye 373 ku50 muImba yeVamiririri. 