It was a turning point because british always had more power then u.s, then france joined u.s so u.s had more power, it showed that countries had trust in u.s.
D.is your answer ok hope i help
Tonkin Gulf Resolution. I hope that helped ^.^
Explanation:
The resolution was passed on August 7, 1964, by the U.S. Congress after an alleged attack on two U.S. naval destroyers stationed off the coast of Vietnam. The Gulf of Tonkin Resolution effectively launched America’s full-scale involvement in the Vietnam War.
https://www.history.com/topics/vietnam-war/gulf-of-tonkin-resolution-1
I hope that helps :)