Trump is not Goldwater and both the country and the Republican Party were very different in 1964 than they are today. With that in mind, there are some parallels worth considering. I've already posted the Daisy spot in response to Cruz's comments on nuclear weapons. LBJ's ads are even more relevant to recent developments in the Trump campaign.
Goldwater had similar issues. [Make sure to mute the sound if you're in public.]
The Living Room Candidate - Transcript
"KKK," Johnson, 1964
MALE NARRATOR: "We represent the majority of the people in Alabama who hate n-----ism, Catholicism, Judaisim, and all the -isms of the whole world." So said Robert Creel of the Alabama Klu Klux Klan. He also said, "I like Barry Goldwater. He needs our help."
As noted many places, the moderate wing of the GOP is freaking out over Trump (see here and here)
The Johnson campaign brilliantly exploited a similar reaction to Goldwater.
The Living Room Candidate - Transcript"Confessions of a Republican," Johnson, 1964
[TEXT: Confessions of a Republican]
REPUBLICAN: I don't know just why they wanted to call this a confession; I certainly don't feel guilty about being a Republican. I've always been a Republican. My father is, his father was, the whole family is a Republican family. I voted for Dwight Eisenhower the first time I ever voted; I voted for Nixon the last time. But when we come to Senator Goldwater, now it seems to me we're up against a very different kind of a man. This man scares me.
Now maybe I'm wrong. A friend of mine just said to me, "Listen, just because a man sounds a little irresponsible during a campaign doesn't mean he's going to act irresponsibly." You know that theory, that the White House makes the man. I don't buy that. You know what I think makes a President - I mean, aside from his judgement, his experience - are the men behind him, his advisors, the cabinet. And so many men with strange ideas are working for Goldwater. You hear a lot about what these guys are against - they seem to be against just about everything - but what are they for?
The hardest thing for me about this whole campaign is to sort out one Goldwater statement from another. A reporter will go to Senator Goldwater and he'll say, "Senator, on such and such a day, you said, and I quote, 'blah blah blah' whatever it is, end quote." And then Goldwater says, "Well, I wouldn't put it that way." I can't follow that. Was he serious when he did put it that way? Is he serious when he says I wouldn't put it that way? I just don't get it. A President ought to mean what he says.
President Johnson, Johnson at least is talking about facts. He says, "Look, we've got the tax cut bill and because of that you get to carry home X number of dollars more every payday. We've got the nuclear test ban and because of that there is X percent less radioactivity in the food." But, but Goldwater, often, I can't figure out just what Goldwater means by the things he says. I read now where he says, "A craven fear of death is sweeping across America. What is that supposed to mean? If he means that people don't want to fight a nuclear war, he's right. I don't. When I read some of these things that Goldwater says about total victory, I get a little worried, you know? I wish I was as sure that Goldwater is as against war as I am that he's against some of these other things. I wish I could believe that he has the imagination to be able to just shut his eyes and picture what this country would look like after a nuclear war.
Sometimes, I wish I'd been at that convention at San Francisco. I mean, I wish I'd been a delegate, I really do. I would have fought, you know. I wouldn't have worried so much about party unity because if you unite behind a man you don't believe in, it's a lie. I tell you, those people who got control of that convention: Who are they? I mean, when the head of the Ku Klux Klan, when all these weird groups come out in favor of the candidate of my party — either they're not Republicans or I'm not.
I've thought about just not voting at this election, just staying home — but you can't do that, that's saying you don't care who wins, and I do care. I think my party made a bad mistake in San Francisco, and I'm going to have to vote against that mistake on the third of November.
MALE NARRATOR: Vote for President Johnson on November 3rd. The stakes are too high for you to stay home.