question france decided to aid the north american colonies in their war for independence primarily because france responses was working to establish democratic rule in european countries was working to establish democratic rule in european countries saw the war as an opportunity to end the international slave trade saw the war as an opportunity to end the international slave trade wanted to weaken the british empire wanted to weaken the british empire was allied with spain, which had already joined the colonists’ cause was allied with spain, which had already joined the colonists’ cause had long been the primary trading partner of the north american colonies