April 6 1917
France, USA and USSR.
The USA was never was a member of the League of Nations, so to answer your question nothing different would have happened because they never joined.
the US got bombed by Japan
It is doubtful the USA will enter another world war anytime soon. The operations in Iraq and Afghanistan still need to be resolved. Other countries really do not want a world war and neither does the USA.
not if the 15 year old is travelling within the USA, but as soon as he or she leaves the USA for Mexico, Canada or any part of the world Yes, then a passport is vital some countries will also require a visa before you enter.
The USA joined in the war because the USA was part of the Triple alliance in the first place, and after Germany attacked the USA's submarines and battleships, they then joined the war in 1917.
Because of the Japanese attack on Pearl Harbour.
Any country that wasn't Germany or Austria, Great Britain, France or the USA.
In world war1 in was the Prime Ministers of Lloyd George of England, George Clemanceau of France and Woodrow Wilson of USA. In World War two, it was Neville Chanberlain followed by Winston Churchill of England and of course Adolf Hitler
The Japanese attacked the USA at Pearl Harbor, Hawaii on December 7, 1941.
The reason the US entered war world 2 was that Japan had destroyed the USA's base at Pearl Harbor in Hawaii.
Primarily: France, Britain, Russia, Italy vs. Germany, Austria The USA came in on the side of France and Britain very late in the war, but both sides were exhausted, so the fresh troops made a big difference.