Whoa, Carter had reached 60% in the middle of '76? Damn.
It was February 1976, not the middle of 1976. And that was before John Anderson entered and when many Americans felt super-patriotic due to the hostage crisis and said they were supporting Carter.
No, 1976 was when Gerald Ford was President lol.
Yeah, Ford surged late against Carter. The only explanation is that it's Carter and he really bombed towards the end. I'm sure a lot of party strategists thought to themselves "uh oh" after looking at the election results compared to the polls just months earlier.