When I met with Crystal Mason recently at her home in Rendon, Texas, we sat on a wide couch that served as the center of her domain, with plenty of space for children, grandchildren, nephews, and nieces. Their photographs filled the house. Mason’s mother called to her from another room, needing advice; later, her eight-month-old grandson, Carter, joined us on the couch after waking up from an afternoon nap. For hours that day, Mason spoke candidly about the illegal-voting case that has consumed her life for half a decade. With us was one of her lawyers, Alison Grinter Allen. If...