Volation of freedom of the seas
The main reason for the American entry into World War I was the German use of submarine warfare (1917), violating the United State right to freedom of the seas. German was suffering from near- starvation due to a lack of supplies and food. German military leaders feared they would lose the war unless they could defeat Britain and France quickly. They therefore took a risk by announcing they would they would sink any ship in the blockaded areas. This was a clear violation of the American principle of freedom of the seas that neutral parties have the right to ship non-war goods to nations at war. When German followed up its threat by ordering its submarines to sink three unarmed American merchant vessels, Wilson asked congress for a declaration of war against German.