Prior to the American Revolutionary War, Great Britain was ruling and fighting many other countries. They were the powerhouse and it was difficult for other countries to win conflicts with them. In a sense, the countries as a whole waited during the war to see what would happen.
They let the colonists start the war before they would intervene. The Battle of Saratoga was the turning point in the war because it showed that the colonists could win the war and it allowed other countries to help the colonists against Great Britain.
France became an ally with America even though they fought in the past because they wanted the colonists to win against Great Britain. They did this because they didn’t want Great Britain to become stronger and acquire more land.