One thing I have noticed in two elections is that calling your opponent unfit doesn’t work. In the last election in Canada the conservatives ran many ads saying Trudeau just wasn’t ready to be PM and now the same thing H tried to do with Trump. Both times the strategy failed.
It was new and shock when Bill Clinton did it to Bush and Dole, but doesn’t work anymore ...
Lots of advertising works because of fear. Both Trump and Clinton used it in their advertising. But lots of people could see that there was a real reason to fear open borders, crappy trade agreements, terrorism, etc.
And lots of people also bought into the notion to be afraid of a sometimes brash guy that didn’t always talk nice. And now those same people, and their children, are afraid of the bogeyman that Hillary and the MSM created.