Ever wonder how we got LBJ, the Vietnam War, the welfare state, and unlimited Third World immigration?
It was mainly the JFK assassination, but also hysterical anti-Republican propaganda in 1964. This video is an example: Confessions of a Republican (LBJ 1964 Presidential campaign commercial) VTR 4568-26.
There is not really any substantive argument against Goldwater. It is mainly sneaky psychological tricks to make you think that Goldwater is somehow untrustworthy, or unproven, or associates with the wrong people.
Here is the more famous Daisy ad. It showed a nuclear bomb explosion while a girl was picking daisy petals.
I expect to see much nastier anti-Republican ads, if the nominee is either Donald Trump or Ted Cruz.