A looser rein is to be expected with a Western style of ride but a little less slack—see how far wide he has to swing his hands to navigate the assembled press?—would give the dishonorable judge the increased control this particular situation demands. Beyond that, his failure to steady himself using his seat (sorry to draw your attention there) or even the stirrups, cause him to rely on the reins to stay upright every time Sassy lunges forward. In the simplest terms: Pressure on the reins communicates to a horse that she should slow down or stop while pressure from the rider’s legs communicates that the horse should go or speed up. So while Moore is trying to ride away from the polling place, he’s also jerking his horse in the mouth, giving the animal conflicting signals and acting like a real asshole.