I think parent actually meant plurality, at least that’s how I read it.

However these numbers are quite interesting. Some people attribute Nixon’s second election to his promise of withdrawing from Vietnam and one can easily blame the war for the problematic 1968 election for the democrats. LBJ was probably even gonna be the first sitting president to loose in a primary before he announced his non-bid.

I’m guessing the 1964 for election he was pretty much just riding the popularity of the recently assassinated John F. Kennedy. (Plus the war hadn’t escalated at this point).