Yes, they sure did warn Americans. I recall hearing something completely different than what Goldwater is quoted above saying.
That's the advantage the leftists still use when taking one comment and making it into something entirely different.
The leftists' strategy have tragic consequences.
The historical fact is, LBJ and his sh!t-for-brains defense secretary Robert McNamara screwed the pooch in Vietnam and turned a conflict which could have been over in 90 days into a protracted war and the reason that happened is that the LBJ ‘Rat Administration let itself be conned into fighting that conflict on the ENEMY’s terms, and not on ours.
Johnson could have wrung a surrender out of the Communists by relentless bombing day and bloody night, 24 hours around the clock, mining and shutting down Haiphong Harbor (which Nixon finally did in 1970), and LBJ *might* have been able to enter the ‘68 election cycle on the slogan of ‘He Won the War’.