As for America entering WWI, we tried to avoid entry,
but Germany insisted.
At the beginning of 1917 Germany decided to resume all-out submarine warfare on every commercial ship headed toward Britain, realizing that this decision would almost certainly mean war with the United States. Germany also offered a military alliance to Mexico in the Zimmermann Telegram. Publication of that offer outraged Americans just as German U-boats (submarines) started sinking American ships in the North Atlantic. Wilson asked Congress for "a war to end all wars" that would "make the world safe for democracy", and Congress voted to declare war on Germany on April 6, 1917.[4] On December 7, 1917, the US declared war on the Austro-Hungarian Empire.[5][6]
https://en.wikipedia.org/wiki/Americ...to_World_War_I