Relatively minor POD, but assuming the US loses the Battle of Ia Drang in '65 Vietnam, what would be the effects, if any, on the rest of the Vietnam War?
Here's the battle for those who don't know:
http://en.wikipedia.org/wiki/Battle_of_Ia_Drang
South Vietnam may not last long enough for the American public response to be anything other then a post-mortem.
It depends on whose version of the state of the ARVN you take. According to Dennis Warner - who had been covering the fighting since 1946 - the South Vietnamese were months away from total collapse at this point. They were hanging on by their fingernails. Others insist it was not quite that bad, some gave it as much as a year. Warners's 'Not with Guns Alone' would be one source of info on the South Vietnamese mood at the time.
The Ia Drang battle was part of the same strategy the NVA actually used ten years later to win the war. Attack a major outpost in the central highlands, ambush and destroy the relief force then swallow up the plateau cities and sweep to the coast cutting the country in half. The rest collapses in a screaming heap and Saigon becomes a communist capital. The end.
The Ia Drang was the 'ambush and destroy the relief force' part. Foreign forces in country were too small to counter a collapse of the Army of the Republic of Vietnam. If the 1st of the Seventh had been destroyed whatever morale the ARVN still had would vanish.
When the French were running the war they had a term for what the US forces in various encircled outposts would have gone through trying to fight their way out to the coast. "Croutons in the soup" was the term for the units, "Looking like Christ off the cross" was the term for what any survivors who straggled in to surviving outpost weeks later looked like.
That kind of ending would have seen President Johnson impeached amid the uproar. The image of the US military would take a huge hit. Major effects on the credibility of the western world and anti-communist viewpoints in third world countries.
That the whole airmobile idea might be seen as discredited would be a trivial issue by comparison.