Under Supreme Court precedent, gerrymandering to benefit a political party or politician is generally allowed. Gerrymandering on account of race, on the other hand, has many constitutional restrictions. The distinction can be a difficult one. Justice Kennedy explores it in this conversation with Pildes, who provides a powerful example: “If, for partisan purposes, a legislature passed a race-based barrier to voting, that would surely be unconstitutional.”
Shortly after, Pildes mentions the “Shaw line of case.” These cases, Shaw. v. Reno (1993), Miller v. Johnson (1995), and Hunt v. Cromartie (2001), have generally established that race cannot “predominate” over other traditional factors used in redistricting.