With the exception of 2000 and 2008 which each have their own sorid stories the market has generally been in positive territory for presidential election years in recent times.
Of course anything can happen with the market. Better to invest in diversified funds over decades.
My comment on this—young folks should think long term and not worry about anything.
Older folks should be more cautious—especially if they have what they need and will be fine preserving what they have.