Well, that's one way
Urban renewal is still the primary tool, though.
Anyway…
How to De-power a Minority Voting Bloc
Here is an interesting article about power sharing between factions at the city level. One widely known activity of city and local governments has been consolidation, merging and annexation of nearby city, local, and county governments.
I think such stories are intersting. Usually they center around small-town fueds or corporate development. The article below tags the issue from the racial angle and begins to answer the questions: what happens when a groups that was 37% of the municipal population goes to less than 15% -and- was this power dilution intentional?