After his campaign promise of keeping america out of the war in 1916, how did wilson garner american support for the war?

President Woodrow Wilson was able to garner American support to join the allied powers, even though he didn't want to join the war and his campaign slogan was " He kept us out of the war", because of the resume of the German unrestricted submarine warfare that cost american economy and also american lives like the sinking of British ocean liner Lusitania where there are more than a hundred american passengers and the interception of the Zimmerman note that in which if the Mexican government would join to the central powers and would win the war the territory of Texas, Arizona and New Mexico would return to Mexico.