Collected and (occasionally) composed

First, the Obamas have a magic about them as a couple to which most people respond positively. If you go to any event where the Obamas are standing next to each other, turn around and look at the crowd and you will see many people — especially women — smiling. Male political operatives often underestimate how much women like to see genuinely happy couples in politics. Political wives are invisible to many male voters, but women voters tend to observe them carefully, sussing out whether a political wife is going through the motions out of duty or ambition rather than love. And their perception of the wife’s emotions and role influences their judgment of the qualities of the candidate to whom she is married (which in my opinion, is perfectly rational).

[Second,] 

When the President is with his wife, his humanity comes out in a way that it often does not in other circumstances. The facade of the distant academic cracks open, revealing that skinny, accessible and idealistic young man who is still happily ensorcelled by his brilliant companion. And at that moment, many people in our cynical, brutal and heartless electoral process pause for a moment and remember that Barack Obama is a human being, and they like him.