Where's Obama's proof of citizenship?

Both presidential candidates have been accused of not meeting the Constitutional requirement that only "natural-born" citizens hold the presidency.

Last month a federal judge threw out a lawsuit seeking to remove John McCain from the California ballot because he was born in the Panama Canal Zone:

Judge William Alsup of Federal District Court ruled late Tuesday that the law at the time of Mr. McCain’s birth automatically granted citizenship to offspring of American citizens.

Mr. McCain’s parents were both citizens when he was born on Aug. 29, 1936, in the Panama Canal Zone, an American territory where his father was stationed with the Navy.

Obama still faces a legal challenge to his constitutional eligibility to be president. A lawsuit, Berg v. Obama, brought by Philip J. Berg, a Philadelphia attorney, alleges Obama is not eligible to be president.

Instead of producing records proving Obama is a natural born citizen, Obama and the Democratic National Committee have filed a motion seeking a protective order to block production of documents until a motion to dismiss is the law suit is ruled on by the court. Obama and the Democratic National Committee also claim attorney Berg has no standing - has no right - to bring the lawsuit.

What is it that Obama and the Democratic National Committee are trying to hide? Why not just produce documents that prove Obama's citizenship and make the lawsuit go away?

Watch the following video in which, Berg talks about his lawsuit:

I repeat, what is it that Obama and the Democratic National Committee are trying to hide? If Obama can post his birth certificate on his website why can't he provide it to the court?