How to Get Away With Gerrymandering

Luxury cabanas atop Austin’s JW Marriott kept state legislators cool poolside as August-in-Texas temperatures soared above 103 degrees during each day of the American Legislative Exchange Council’s 2019 annual meeting. The gathered Republican officials could enjoy a $14 rooftop Peppered Paloma cocktail with Patrón silver, housemade grapefruit poblano soda, and Chilean salt, all while gazing over Lady Bird Lake and the nearby state Capitol, or catching a ballgame on the cabana’s 55-inch private TV.

Downstairs, meanwhile, five of the GOP’s most seasoned redistricting minds and über-lawyers would teach them the...