Why was it difficult for American soldiers to tell friend from foe in the Vietnam war?
Two reasons:
1. Prior to the Tonkin Gulf Incidents in '64, the war in South
Vietnam was fought by guerrillas (VC). As a rule, guerrillas DID
NOT wear uniforms and they utilized CAPTURED weapons. Thusly, you
had "anyone" (man, woman, or child) walking around with a gun (US
supplied or captured from previous wars: US Rifle 1903 bolt action
Springfield, British Lee Enfield bolt action .303s, WWII Japanese
7.7mm Arisaka bolt action rifles, US Tommy Guns, US M1 carbines, M1
Garand US Rifles, .45 pistols, etc.). Until the entry of the
uniformed NVA from North Vietnam who came equipped with
Soviet/Chicom AK47s or SKSs in 1965...there was a problem.
2. Secondly, all wars, and Vietnam was no exception, have had
incidents in which the enemy deployed innocent civilians as
terrorists.