Goldwater had the GOPe,the media and the Democrats against him. Cruz will be facing the same enemies.
Reagan did as well. It was amazing to see—and I was on the other side then. Personality and leadership instincts make a huge difference. Goldwater needed a personality transplant. He had clarity, but not much warmth. This missing element showed up in the fact that he was no social conservative.
Lefties in my college dorm were making up hate songs against a potential President Reagan five years before he was elected. I was anti-Communist, but I wasn't pro-Reagan yet. It seems incredible now, since I saw the Communists and wimps lined up against him. I didn't realize that Carter was on the other side, and that his respectability was pure camouflage. It took me till 1984 to vote for Reagan. Thank God most Americans weren't so thick.
The job of a good candidate and his political organization is to draw connections in the voters' minds, to show which ideas have what consequences.