While nothing the birthers do will change the present situation a more important reason to let them try is, that if this the issue is not resolved than any another country can send one of their citizens here to have a child (US citizen) then raise them as whatever (communist Chinese) an have them become President with the actual purpose of destroying this country.
As it stands now this would be legal and we could not stop it.
As it stands now the charges are denied and unproven in a court of law.
Therefore, no precidence has been set.
Future attempts would need to be challenged and stopped BEFORE the election.