re: What if the US had left Vietnam in 1966?
Knowing what we know about Vietnam now, it's obvious the war in Vietnam was a waste of time, money and lives.
And leaving Vietnam much earlier would have meant far fewer casualties.
And Vietnam would anyway have evolved to what it is now.
There would have been more money for more Apollo flights, more money for the shuttle, a space station and a space tug.
If the US can't leave Iraq, will NASA get back to the Moon?