What should I ask David Rubinstein?

I will be doing a Conversation with him.  From Wikipedia:

David Mark Rubenstein (born August 11, 1949) is an American billionaire businessman. A former government official and lawyer, he is a co-founder and co-executive chairman of the private equity firm The Carlyle Group,^[ a global private equity investment company based in Washington, D.C. He is chairman of the Kennedy Center for the Performing Arts, former chairman of the Smithsonian Institution, chairman of the Council on Foreign Relations, and president of The Economic Club of Washington, D.C. According to Forbes, Rubenstein has a net worth of $3.7 billion.

David also has a new book out The American Experiment: Dialogues on a Dream.  So what should I ask him?