By Jon Frandsen, Senior Editor September 5, 2008 One overlooked aspect of John McCain's acceptance speech could end up being an important moment of the campaign -- and one of its most indelible images. Anyone watching who harbored doubts about McCain's vitality and sharpness certainly would have been impressed when McCain wound up his speech with a supercharged plea to "fight with me. Fight with me. ... Stand up, stand up, stand up and fight."McCain is not a particularly gifted orator and his appeal generally lies in his steadfastness and directness. But in that moment Thursday night McCain displayed every bit as much vigor, purpose and ability to inspire as Barack Obama, who is a quarter century younger than McCain.McCain's rouser of a closing -- which was, Gov. Sarah Palin notwithstanding, the single-most electrifying moment in St. Paul's Xcel Energy Center -- was not the last word on McCain's age, especially given the thrilling Palin's lack of experience. Nor was it a direct and defining answer to critics in the mold of Ronald Reagan's crack in 1984 that he would not seek to take advantage of opponent Walter Mondale's age or lack of experience. Mondale at that point had already served four years as vice president on top of a long Senate career. But McCain's performance may be even more important than a memorable soundbite. He didn't answer critics -- he simply showed that they were wrong, in a moment that we may see again in campaigns ads between now and November.