April 1917
The bombing of Pearl Harbor.
America did get involved
America.
How did who become involved with the war effort?
A strong reluctance to become involved in future wars.
The Townshend acts were one of the main things that led the US Revolutionary War. The acts involved the parliament of Britain and the colonists in what would become America.
The Korean war
Given that the revolutionary war is the war that created the USA, it could be said that the USA was involved from the start.
russia
Spain and America
it was 2004