See answer below.
Immigration numbers did not decline.
The Vietnam War demonstrated to the world, that the US would make a stand against communist aggression. The loss of South Vietnam was a temporary blow to US morale.
The US was waging war against the nation of NORTH VIETNAM. The US is "not" waging war against the country of Iraq. The US is trying to establish law, order, and stability to the region.
The government decided to negotiate an end to the war
In the US, it resulted in an all volunteer Armed Forces.
It mirrored US effects.
Division.
North Vietnam was the scene of the AIR WAR during the Vietnam War. N. Vietnam was bombed by air units from the US Navy and US Air Force. US Marine Corps units bombed in South Vietnam in support of their ground Marines. North Vietnam defended itself in North Vietnam with SAM sites and NVAF MiG 17, 19, and MiG 21 jet interceptors.
We were at war with Vietnam because they disagreed with us about something.
Two readily visible effects are that it eliminated the military draft and lowered the voting age from 21 to 18.
Vietnam
The US is not at war Iraq. The US was at war with a nation called North Vietnam.