Yes, the above answer is correct. But I believe it was Winston Churchill's Rapport with the President of America, Franklin Delano Roosevelt, that led to the USA coming to the help of Britain and her Allies. At first it was lease-lend - helping with old ships, etc, but in return in Britain allowing America to set up facilities in British held territories. But, once Japan attacked Pearl Harbour, America were able to publically declare war - and America geared up to help Britain and the Allies in defeating Germany, and Japan.
Likely Churchill.
By sinking them!
German submarines sank an enormous amount of British and Commonwealth shipping in the Atlantic and for a time in 1916 food stocks in Britain were down to about six weeks' supply. German submarines aslo sank some neutral ships and by sinking American ships they brought the U.S. into the war.
Unrestrictive sinkings (sinking without a warning).
They were at war with each other.
Atlantic.
World War 1.
The sinking of the Lusitania and German submarines in American waters
The Zimmerman telegram, (which the British intercepted and gave to the USA), in which Germany tried to get Mexico to declare war on the USA. Also the German submarines were sinking unarmed civilian ships sailing from neutral countries.
U-boats. (German submarines)
by avoiding sinking of US vessels by German submarines............... but, after Japan bombed Pearl Harbor, Germany declared was on the U.S.
The united states entered world war 1 because of the sinking of US ships (including the the Lusitania) by German submarines