Remember that Obama went out of his way to invite Muslim Brotherhood representatives to his speech in Cairo in June 2009. So it is unlikely that he even sees the need to stand up to them.

"Muslim Brotherhood Wants War With Israel," from [1] Forex Crunch, January 31 (thanks to [2] Pamela Geller):

Mohamed Ghanem, one of the leaders of the Muslim Brotherhood in Egypt, calls Egypt to stop pumping gas to Israel and prepare the Egyptian army for a war with it's [sic] eastern neighbor.

Speaking with Iranian television station Al-Alam, Mohamed Ghanem blamed Israel for supporting Hosni Mubarak's regime. Ghanem also said that the Egyptian police and army won't be able to stop the Muslim Brotherhood movement....