I remember not liking him when he ran for President in 1964 but the prediction above is interesting, as is this comment from the Reddit thread:
Jewish father, Protestant mother, he hated the mixing of religion and politics. He was totally different than the Republicans of today. From Wikipedia: "In response to Moral Majority founder Jerry Falwell's opposition to the nomination of Sandra Day O'Connor to the Supreme Court, of which Falwell had said, "Every good Christian should be concerned", Goldwater retorted: "Every good Christian ought to kick Falwell right in the ass." (According to John Dean, Goldwater actually suggested that good Christians ought to kick Falwell in the "nuts", but the news media "changed the anatomical reference.")
Goldwater also had harsh words for his one-time political protege, President Reagan, particularly after the Iran-Contra Affair became public in 1986. Journalist Robert MacNeil, a friend of Goldwater's from the 1964 Presidential campaign, recalled interviewing him in his office shortly afterward. "He was sitting in his office with his hands on his cane ... and he said to me, 'Well, aren't you going to ask me about the Iran arms sales?' It had just been announced that the Reagan administration had sold arms to Iran. And I said, 'Well, if I asked you, what would you say?' He said, 'I'd say it's the god-damned stupidest foreign policy blunder this country's ever made!'"."
Some of Goldwater's statements in the 1990s aggravated many social conservatives. He endorsed Democrat Karan English in an Arizona congressional race, urged Republicans to lay off Bill Clinton over the Whitewater scandal, and criticized the military's ban on homosexuals: "Everyone knows that gays have served honorably in the military since at least the time of Julius Caesar." He also said, "You don't need to be 'straight' to fight and die for your country. You just need to shoot straight."
A few years before his death he went so far as to address establishment Republicans by saying, "Do not associate my name with anything you do. You are extremists, and you've hurt the Republican party much more than the Democrats have." In 1996, he told Bob Dole, whose own presidential campaign received lukewarm support from conservative Republicans: "We're the new liberals of the Republican party. Can you imagine that?" In that same year, with Senator Dennis DeConcini, Goldwater endorsed an Arizona initiative to legalize medical marijuana against the countervailing opinion of social conservatives."