I find this ad by Elbert Guillory against Mary Landrieu to be both relevant and poignant to today's election cycle.

In my mind, if the minorities and the Bernie fans simply fall in line and vote Democratic, then on what basis do they have to complain
when things, once again, don't improve in their direction under Democratic leadership. Sometimes you just have to send a message that will be heard loud and clear.

Elbert Guillory: Mary Landrieu is Not Helping Blacks - YouTube