It is entirely possible that the top echelons of political power in the United States would be completely absent a Protestant representative. The religious affiliation could very likely look as such:

President – LDS
Vice President – Catholic

Senate Majority Leader – LDS
Speaker of the House – Catholic (Boehner or Pelosi) or Jewish (if Cantor were to stage a coup).

Supreme Court of the United States – 6 Catholic / 3 Jewish (0 Protestant)