Amid swirling scandals over North Carolina Lt. Gov. Mark Robinson and Louisiana Rep. Clay Higgins, a former professor at the U.S. Naval War College argued Thursday that the “limit for this kind of ghastliness does not seem to exist” for the GOP. A damning CNN report linked Robinson, the state’s gubernatorial candidate, to pro-slavery and pro-Nazi content on a porn site. Robinson has denied reporting that he posted comments on the site Nude Africa that he was a “black NAZI” who expressed appreciation for slavery and transgender pornography. This week, Higgins, a Louisiana Republican, quietly de…