Re. "A Popular President"

No mystery...
I think the voting public honestly believed Bill Clinton represented the American people and their interests.
That's it, in a nutshell.

(He might have failed in his outlook on things like NAFTA, and made grave misjudgments and mistakes... he might even possess an extremely immature and narcissistic personality still, but this trumps all that: I think the voting public honestly believed Bill Clinton represented the American people and their interests.)