M aps can guide us home. They show us where we are, where we have been and where we might go. Electoral maps can do something even more sinister, though. They often tell us what and who is allowed to matter. They can decide, before a single ballot is cast, whether an entire voting bloc will become powerful or be buried by the design of a party that is indifferent – at best – to their needs and wants. Memphis is the latest warning. Tennessee ’s largest majority-Black city can vote, organize, turn out, remember and resist – and still be cut into pieces by politicians who fear what that city might do with power. This week, Republicans carved up the Memphis-centered congressional district, dividing its only majority-Black district into three Republican-leaning seats while weakening voter-notice requirements in the process. Gerrymandering, at its most brutal, does more than help one party win. It teaches a community that even overwhelming local political will can be made irrelevant by a map.…