...If he has done nothing else, and he has done a great deal, Barack Obama has developed an aesthetic of cool that is his alone. It expands and extends from the way he does his job; the video prior to his appearance emphasized how he always was the calm presence in the middle of heated policy debates. It also includes the way he has carried himself in office, and the way he has carried the office itself—lightly, in its ceremonial aspects, but carefully and reverently in those parts of the job that belong most importantly to the rest of us.

...The president is all those things—jazz musician, torch singer, politician, president—all fashioned from his own aesthetic derived from the hidden music he found in our common history. He appropriated optimism and the best elements of that tired, loaded concept called American Exceptionalism. My lord, he even jacked Ronald Reagan, ringing his own changes on the shining city on the hill. He is cool in all the ways that matter.

...And, suddenly, just like that, it was done. Barack Obama had given the last great speech of his career as president. There will be other appearances on other stages—out on the stump for HRC, probably an eloquent valedictory when he leaves office—but this was the last time a really big stage would be his alone and he played it up to the rafters. They cranked the Stevie Wonder in the arena and the Louisiana delegation danced and sang along. "I've been such an instrumental part of the Obama campaign, and then to be a supporter of all his policies, to see that it's all coming to an end, but it's not coming to an end," said Senator Karen Carter Peterson, the state Democratic chairperson. "But it's not really coming to an end because we're starting another chapter with another historic moment. God is good."

On stage a young black man, the president of the United States, warmly embraced an older white woman in front of god and all the world. It is now an iconic photograph. If it had occurred on a weed-choked street in Mississippi within the lifetime of many of the people who were cheering the moment, the young man might have been beaten, burned, hung, thrown into a river with a cotton fan tied to his neck.