Question:

On July 7th, 2009 a movie is coming out called "2012" and is based on the Mayan calendar's prediction that the world ends in the titled year. It stars a great cast, including Oliver Platt, John Cusack, Amanda Peet, and others.
Danny Glover stars as "President Wilson" and Thandie Newton stars as Laura Wilson, the "First Daughter."

Now, probably they chose a black actor to play the president because Obama will be in office at the time, but the portrayal of Thandie Newton as the First Daughter made me wonder:

What is the governmental protocol for those titles? Because, in case you hadn't heard, Obama has two daughters.
Is Malia referred to as "First Daughter" and Natasha referred to as "Second Daughter"? And what if, God forbid, the President's wife passed away and he remarried? Would the new wife be the "Second Lady" because the President's late wife had been the "First Lady"?


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