Professor Richard Thompson Ford is quoted in The Boston Globe commenting that a presidential candidate who portrays levity must choose it carefully:

...because of the inspirational image Obama tries to project - a leader in the tradition of the Rev. Martin Luther King who transcends both racial politics and politics-as-usual - there are limits to how self-deprecating he can be, said Richard Thompson Ford, a professor at Stanford Law School and the author of the book "The Race Card."

"As a charismatic leader," Ford said, "one can't afford to do things that undermine one's charisma."