Like British parliamentary elections in the 18th century, the Republican presidential primary in 2016 may be decided in rotten boroughs.
While the rotten boroughs in Georgian England were the long since abandoned sites of medieval towns where aristocratic landowners could handpick members of parliament, the Republican rotten boroughs are vibrant, heavily populated urban areas in places like New York and Los Angeles.
They just don’t have very many registered Republicans.
The result of gerrymandered redistricting processes and the deep alienation of minority communities from the Republican party is that there are many congressional districts where registered Republicans are almost as rare as unicorns. Republican delegate apportionment rules in many states, however, mean that every congressional district receives three delegates to the convention, regardless of how many GOP voters live there.