Thanks for the correction about Serbia, Art. You are correct. In any case, it was an argument between the Serbs and the Austro-Hungarians that started the misadventure called WWI.

kendall - Yes, the USA could have stayed out of WWI. I suspect they went in for a variety of reasons (realpolitik being what it is), but there was no single reason pressing enough, in my opinion, that they had to go in. It was an option, but it was certainly not a necessity, from the American point of view. Perhaps the US government was concerned about the influence it could bring to bear after the war by using its power to help bring about an Allied victory...and the influence it might lose in the postwar scene by not taking part in that victory. I don't know what was in their minds.

All powers in time of war sink ships like the Lusitania by submarine attack whenever they get the chance to. That's what war is like. The British knew the risk that the liner was running, the passengers knew it too, and they decided to take that risk. They gambled and lost. If it had been a German or Austrian liner that was sunk by a British submarine, you wouldn't have heard nearly as much about it, then or now...because the winners always get a monopoly on moral outrage, don't they? (at least for a few decades immediately after a war)

*** Everybody ends up killing many innocent people during a war. Why? Well, in order to do significant material damage to the opposing side, that's why. It always looks like a good idea at the time. No submarine captain in any navy will let a giant enemy ship pass by during wartime and not attempt to sink it. ***