Actually, I am Joseph Brown and I was in both the Marine Corps (1995-1999) and the Army (2006-2008)....
the branches r USAF, USMC, US Army and now US Space force
Persons in the Army are called Soldiers. there is the USMC and the SAS and although the have them names altogether, they're call solders.
USA (US Army), USN (US Navy), USMC (US Marine Corps), USAF (US Air Force), USCG (US Coast Guard).
The USAF & USN fought in NORTH Vietnam (in the skies); the US Army & USMC fought on the ground in SOUTH Vietnam.
For the USMC it was Iwo Jima. For the US Army & US Navy it was Okinawa. The kamikazes did most of the damage at Okinawa.
Private First Class Jose F. Valdez, US Army, Medal of Honor, WWII. Private Joe P. Martinez, US Army, Medal of Honor, WWII. Private First Class Alejandro R. Renteria, US Army, Medal of Honor, WWII. Staff Sergeant Ambrosio Guillen, USMC, Medal of Honor, Korea. Specialist Fourth Class Daniel D. Fernandez, US Army, Medal of Honor, Vietnam.
Private First Class Jose F. Valdez, US Army, Medal of Honor, WWII. Private Joe P. Martinez, US Army, Medal of Honor, WWII. Private First Class Alejandro R. Renteria, US Army, Medal of Honor, WWII. Staff Sergeant Ambrosio Guillen, USMC, Medal of Honor, Korea. Specialist Fourth Class Daniel D. Fernandez, US Army, Medal of Honor, Vietnam.
Corporal John F. Mackie, Corporal, USMC, first Marine to win the Medal of Honor. Smedley Butler, Major, USMC, two awards, Veracruz and Haiti. Dan Daly, Gunnery Sergeant, USMC, two awards, Boxer Rebellion and Haiti,
US Army
In total 110,000 US military personnel were directly involved in the battle
The Army's official motto is "This We'll Defend." It is on their flag and worn on various uniform insignia. It certainly doesn't have the ring that Semper Fidelis does!
Some websites: Vietnam War Combat Art, US Army Combat Art, USMC Combat Art, US Navy...the Vietnam Experience.