And since they can't actually point to an injury in fact they are failing to establish legal standing to sue. I know all that.
True, but if has nothing to hide, it would be in his interest, and as Mr. Keyes points out, that of the nation, for him to do so.
Why? For him do do so would be to publicly admit the documents he provided earlier are not sufficient, and that the word of the Hawiian officials is not sufficient. No politician is going to voluntarily admit that.
The Hawaiian officials made no statement other than "we have a birth certificate on file". They did not indicate its contents. He would not be admitting that the documents were not sufficient, although they aren't, unless provided directly to a court or other neutral observers. He could just say he "wanted to clear the air". It would gain him brownie points, not cost him any.