Former Democratic U.S. Sen. Claire McCaskill highlighted clear differences between the Republican National Convention and its Democratic counterpart. Speaking to MSNBC’s Nicolle Wallace on Tuesday, the former Missouri lawmaker described the RNC as some clubhouse with a kind of political “no girls allowed” sign. “Yeah, look at the split-screen, Nicolle, between the Republican convention and this one so far,” said McCaskill. “The Republican convention was a testosterone-laden grievance machine, and coming out to the song ‘Men Rule the World’ and Hulk Hogan ripping off his shirt and you know. It …