You would know the truth and better know then which direction to investigate to come up with the facts. You would know whether it would be worth going to the trouble of possibly getting it legally. You really don't know where the knowledge can take you until you find out what the truth about his genetic background is. Plus you could publish it and let Obama have to deal with the fact that, though legally not usable, the truth is out in the public. You could then pressure him to give his DNA to try disprove what you have found, telling the world that he can't.
I know what you mean, and I do understand, but if our group of researchers can’t even get the notion out of freeper’s heads that Stanley Ann Dunham was the mother of zero, because we have never been able to find a sign of her in Hawaii until 1963, imagine what reaction there would be if you suddenly popped up and said, hey, I’ve got DNA that proves zero isn’t related to Stanley Ann Dunham OR the kenyan son of a goat-herder.
They would crucify you.
So, you would know you were on the right track. You might have the satisfaction, but the obots and the disbelievers would destroy you.
Any DNA samples need to be court ordered. And guarded from point A to point B. Pretty dificult to see happening, you can’t even get a bona-fide birth certificate.