If it is his birth certificate, then he was born in Hawaii and is a citizen. Lots of people change their names, particularly black radicals. All this great work was just to prove he is a citizen.
That may be true, but black radicals change to a Muslim name, whick is, in the minds of many, indicative of a group who hate the United States. That might remove much of his political viability if they profer that as an excuse.