Last night, Clint Eastwood was The Man With No Speech. The legendary actor and former mayor of Carmel, Calif., took the stage at the Republican National Convention shortly after 10 p.m. EST to warm the crowd up for Mitt Romney. What followed was a seemingly improvised, 12-minute address to an empty chair he pretended had an invisible Barack Obama. Apparently prompted by an enthusiastic crowd member, Eastwood finished his freewheeling speech by leading the crowd in his classic Dirty Harry line: “Go ahead, make my day.” (Which was the obvious Eastwood quote, of course. But I have to confess: I…