France and England
Germany sunk the ships themselves. They did the WHOLE thing.
The Germans were sinking its supply ships heading for France and England.
Britain prevented any supplies from getting to Germany by sea in WW1, the sinking of supply ships heading for Britain was the only way Germany could retaliate. The fact that some of those ships were American was incidental.
Germany's war with our brethren in England; unrestricted submarine warfare in the Atlantic Ocean.
The sinking of ships carrying Americans
The USA declared war on Germany, after it was revealed that Germany wanted Mexico to declare war on the USA, and after Germany said they would resume submarine sinking of civilian, neutral ships carrying supplies to England and France.
By sinking any suspicious ships or any enemy ships in the perimeter, near the Balkan Peninsula
They didn't. If you are talking about Germany, then in WWI it was because of Germany's submarine warfare, which was sinking U.S. ships. In WWII, they were allied to Japan, who bombed Pearl Harbor.
They thought that Germany would stop sinking ships. <(=fantasia=)>
They tried to cut England of by shooting down their planes and sinking their ships . however they never succeeded.
2 main reasons. Germany kept sinking ships with Americans on them (such as RMS Lusitania). And Germany plotted with Mexico to conquer parts of US and give land back to Mexico.