Buck's got a point.
Perry's polls were sinking badly long before this last screwup. Unfortunately, the debates are almost the only public face some of these candidates have for that large chunk of the public who isn't paying much attention to politics on their own time. Frankly, I have no idea why Republicans are having about one a week, particularly when most of them are being "moderated" by people who would just as soon see every candidate on the stage hit by lightning.