Are you saying another democrat will not be elected president for the next hundred years or are you talking about a black person (regardless of party) specifically? If your talking about democrats specifically, that is highly unlikely because politics usually work like a pendulum. Now if your talking about black people specifically, using that logic is like assuming that all Germans hate Jews 70 years after World War II. That logic thought process is silly and ignorant. I hope I just misunderstood what you meant.