Interesting that you brought up 1976, when Ford fumbled by saying Poland was not behind the Iron Curtain (or something). Reagan the actor turned into a more or less civil performance of an actor playing a part, but he somehow got ahold of Carters' debate prep materials. And Iran magically held onto the hostages until just after the election, when they were somehow released and we somehow released military aid to Iran. But that's another story, and Reagan turned out to be not crazy and actually the better president.
I'm not sure how old you are, but I was around for the Iran Hostage Crisis.
The Iranians didn't "magically" hold on to the hostages. Jimmy Carter was desperately trying to get them back, and the Iranians, who had been totally screwed over by a year of sanctions and international isolation, and they halfway suspected Carter was behind Iraq's invasion of them. (The US largely did turn a blind eye to Saddam's aggression.) So holding the hostages was a big "Fuck You" to Jimmy Carter.
Jimmy Carter was on his way to losing the nomination to Ted Kennedy before the Hostage Crisis hit, and he totally took advantage of it with his "Rose Garden Strategy". The problem was, he milked it too long without trying to resolve it in any meaningful way.
There was no conspiracy, just Carter's incompetence.
If Donald Trump is a bad man who has no business being president, Carter was a good man who had no business being president.