Part of it, as Texas Monthly’s Paul Burka suggests, might be medical or medically-related. Perry had back surgery this summer and the one thing that doctors always tell you about surgery is that it leaves you easily fatigued for months after the operation. Perry noticeably flagged in both debates as they moved past the first half hour. The second debate was two hours long. Back surgery in all likelihood had something to do with his apparent weariness and inarticulate answers.