In the first place the Us was selling arms to Britain So needles to say it was important that the British side won the war, because if they did not the US would lose a fortune. there was also a historical connection between Britain and The USA that had moved well past the times of the revolution. and Japan an Ally of Germany attacked the USA just before Germany declared war on The USA.
In both WWI and WWII Russia allied with Great Britain, France, and the United States.
France, Great Britain, and Russia
The five other countries allied with Great Britain during WWI were France, Russia, Italy, USA, and Serbia.
Canada, USA, Britain, France
Great Britain and France
The allied powers during World War 1 were Britain, France, and Russia. Many of these nations plotted against Germany during the war, causing them to side with the United States.
Triple Entente
Allied powers during World War 2.
France and Great Britain allied with Serbian during World War 1. Serbia was the first country to be attacked in World War 1.
During World War 2, there were thirty-two official countries listed as the Allied Powers. The chief Allied Powers were Great Britain, France, the Soviet Union, the United States and China.
they had a common enemy germany
Russia sided with the Allies, which included Great Britain, France, the United States, Italy, and Japan during World War One.