Yes because if they weren't they would still be fighting in it because they pretty much won every war after the Revolutionary War.
No, it wasn't successful. The government never did declare it a war and didn't put in all that it could have to win.
For North Vietnam it was.
It failed; the communists won the war.
For the communists, yes.
The successful coup was in '63 & supported because Diem had to go.
It's benefiting from US tariffs on China. It's been quite successful in combating Covid.
It did for over 20 years.
Australia was the partner of the US; when we went in, so did they. When we left, they left. Our success, mirrored their success.
No it most certanly was not succesfull.
Vietnam was at war with France before the US intervened in the sixties. In fact, they defeated the French in 1956 and became independent, but divided into North Vietnam and South Vietnam. The Vietnam war the US was in was the result of the North and their communist sympathizers in the South (the Viet Cong) trying to unite the country under communism. When the US pulled out in 1975, they were successful.
The US never invaded Vietnam.
South Vietnam was considered an ally of the US.