We lost Vietnam because of Washington and the Media.
Trump called that right and if you don't agree you are way out in left field.
Partially right. But primarily we lost because the American people gave up. They went for the Leftist "antiwar" propaganda, they dodged, hid out, avoided military duty leaving the fighting to just a few of us, and they just voted for Democrats - which in those days was the same as voting for the enemy.
The number one reason we lost was the paucity of actual men back then.