LBJ's approvals were above 70% during the entirely of 1964 before the election. He would have won in a landslide against Jesus himself.
This. LBJ would have probably won bigger had turnout not been dampened due to the certainty of his victory.
Here's the weird thing about Johnson, though. Apparently he was still paranoid about losing. That's one of the reasons he decided to release the Daisy Ad. No candidate confident of his victory would have released an advertisement that was so controversial. After he barely won his first senate race, I don't think LBJ ever took an election for granted.
