Very good point about vice president choice, a very progressive pick would hurt the markets. As to the election if it looks like in sept that biden is going to win big, then the market gets hit with a 10% correction then, but runs up into the election and after, IMHO
Historically, markets do much better under democratic presidents than under republican ones.
The economy under Obama grew much better than under trump, even if you only look at 2017 to 2019. I recently wrote a book with my uncle, and GDP was not nearly as strong in those 3 years at it had been in the 8 years under obama.