Now that he is in office it is up to "us" prove he should not be there.
If I were zero and thank heavens I’m not and I had the original birth certificate in hand, I’d never show it until court ordered to do so.
I’d wait until the start of the 2012 campaign and then show it and say, “look at this you right wingers”.
There’s absolutely no incentive for him to show it, it’s not like he’s spending his own money to defend himself against these accusations.
He may or may not be a natural born citizen but I won’t hold my breath waiting for him to prove it.