How effective are scandals?

[McGarnagle]

If it's a Trump scandal, it's just another day of the week. His base is almost certainly not going to change their minds about him at this point under any circumstances.

If it's a Democratic scandal, it could be only very mildly damaging to a candidacy, like Obama and Rev. Wright - Obama was able to successfully draw a distinction between his candidacy and Wright's rhetoric, and ended up winning by a wider margin than anyone thought possible a year previously.

It could also be very damaging or fatal to a Democratic candidacy if it's a sexual harassment scandal or blackface scandal. There's a reason nobody mentions Al Franken or Ralph Northam as potential future candidates for president.