Michelle Obama's Role in Heath Care Reform

On Friday, the First Lady addressed the public about health care in the United States today.  An article from CNN that I read described Michelle Obama to be "humanizing" the issue.  She told stories of experiences from her own life supporting universal health care and its importance to every American. 

Michelle Obama has a certain power over America that the President does not; she has the ability to make people feel more related to political issues.  She has the ability to move away from logistics and make an issue more "human".  She really is playing her role as First Lady.  Why does the public feel so compelled to listen to her words?  Why does the public feel that they can relate to her?  Is the First Lady always a woman we can relate to?