Liberal-dominated political entities exhibit what I’m going to call the Dinkens effect. They have to elect their first black mayor, governor, senator, or even president just to prove to themselves how wonderful they are. After they’ve gotten that out of their system, they go back to evaluating and voting for candidates based upon their perceived qualifications and competence.
If the first black mayor, governor, etc. turns out to be a great or even moderately competent one, future black candidates will be evaluated according to their perceived ability to do the job. If, however, the first turns out to be utterly incompetent and/or corrupt, it sets back future black candidates for generations. It will probably be decades before New York City elects another black mayor after David Dinkens, Los Angeles elects another black mayor after Tom Bradley, Chicago after Harold Washington, and America elects another black president after Obama.
Of course, if blacks - the most racist voters on the planet - completely dominate the political entity, it will keep electing black leaders regardless of their competence. See Detroit. Of course, we can see where that got them.
Someday America will see another black president. It will probably not happen again until mid-century or later, by which time the catastrophically incompetent, corrupt, and abusive presidency of Obama has faded from memory.