The US Civil War (1861-1865) & the Vietnam War (1961-1975).
49 000 soldiers were sent to fight in the Vietnam war.
Thailand sent troops to South Vietnam.
The war began when President Eisenhower sent US Advisers to Vietnam in 1955; however most historians consider the starting date of the war to be 1961, when President Kennedy sent the Special Forces (Green Beret) to Vietnam.
The United States went into war with Vietnam in the year 1965.
Prime Minister of Australia, sent his men to Vietnam.
he sent the u.s. military to the Vietnam in 1955
Korean War Vietnam War
During the Vietnam War, all combatants (including North Vietnam) used draftees except for the New Zealanders, they sent volunteers to South Vietnam.
Thailand was an ally of the US.
Australia was an ally of the US and sent troops to fight in both WWII and Vietnam.
The US sent over 2 1/2 million men. See website: Vietnam War