The Oregon Country was originally claimed by Great Britain, France, Russia, and Spain; the Spanish claim was later taken up by the United States. The extent of the region being claimed was vague at first, evolving over decades into the specific borders specified in the US-British treaty of 1818.
The USSR’s help in defeating Japan. The US wanted Stalin to attack from above during the invasion of Japan, aka Operation August Storm. This happened with the Soviet invasion of Manchuria.
