Lyndon Johnson actually said...

I give you my pledge: We shall never let you down, nor your fighting comrades, nor the 15 million people of South Vietnam, nor the hundreds ...

One day when they know peace, the whole world will acknowledge that what you have done here was worth the price.

The need for food transcends all the divisions man has created for himself.

They also know what is at stake and are willing to fight and die for it.