A couple of decades ago, Nate Persily, a law professor at Stanford University, was asked by a court to help draw up the boundaries for a political district in Georgia after a bitter political fight.

The existing boundaries were, as in many US districts, a crazy mess of wiggles. Persily sketched out a neat, logical square on a map. Then he discovered there was a mountain that split the district in two — which unleashed a new fight.

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“Redistricting is an impossible problem to solve,” Persily lamented last week at the Social Science Foo conference in San Francisco.

He presented maps showing disputed districts in places such as North Carolina, Florida and Pennsylvania. These were marked with such head-spinningly bizarre lines that they might have been drawn by a hyperactive toddler. “You can either be blind or be fair when you draw a district,” he told us. “You cannot be both.”

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In some instances, state courts have intervened. As Persily has warned, this means that “courts are not mere referees of the redistricting process; they have become active players often placed in the uncomfortable role of determining winners and losers in redistricting, and, therefore, elections”.