hoist on one's own petard

— Sword in hand, U. S. Grant took up the rear as the procession hut-hutted up the front steps past a blurb from Publishers Weekly (“A lazy-day literary luncheon turns into an afternoon of terror as five novelists in the habit of using public figures for their own artistic purposes are hoist on their own petard—shocking, but overdue”), and on into the grimly compelling first novel.