Who was the american president during wwi? what was his campaign slogan in 1916?

Woodrow Wilson and the slogan was "He has kept us out of war"

Woodrow Wilson was the president and served in office from 1913 to 1921 and led America through World War I (1914-1918). The Democrats built their campaign around the slogan, "He Kept Us Out of War," saying a Republican victory would mean war with both Mexico and Germany. Wilson's position was probably critical in winning the Western states. (via research & google)

Hope this helps!

the roman army grew in size and became dominant in the mediterranean region.

when he becomes king