If they never built it, it couldnt have been sunk
There are two primary causes for the US entering World War I. First and foremost is the sinking of the Lustitania and Unrestricted Submarine Warfare. The concept of Unrestricted Submarine Warface (USW) was that any ship, flying anyflag, neutral country or not, around the coast of the United Kingdom would be treated as a warship, and promptly attacked. When the Lusitania was sunk in 1914: roughly 120 American civilians were killed. Afterwords, Germany suspended USW until 1917. In 1917 Germany resumed USW, after repeated warnings from the US that it would mean War.The second reason is the Zimmerman Telegram, sent to Mexico on Germany's behalf. It promised German support if Mexico would open a domestic front and invade the US, should it come to war. Naturally, the citizenry was outraged.
Yes, i think the Germans did have the right to torpedo the Lusitania. Only because they thought the Lusitania was carrying arms to help the British. Yet they were right. It is terrible that 128 Americans and lots of british were on this ship, and were killed when they mostly didnt know the arms were even on the boat. the Germans took their chances by doing this, but it was for their country!