Why did America need France to join the fight against British?

The second agreement, the Treaty of Alliance, made the fledgling United States and France allies against Great Britain in the Revolutionary War. The French decided to back the U.S. in its military efforts until the U.S. had full independence from Great Britain. (To get independence from Great Britain)

Explanation: Google

The second agreement, the Treaty of Alliance, made the fledgling United States and France allies against Great Britain in the Revolutionary War. The French decided to back the U.S. in its military efforts until the U.S. had full independence from Great Britain.