Obama aide: End of Assad regime will serve severe blow to Iran http://www.haaretz.com/news/diplomacy-defense/obama-aide-end-of-assad-regime-will-serve-severe-blow-to-iran-1.397144  The toppling of Syrian President Bashar Assad's regime would serve a serious blow to Iran and would serve to further isolate the Islamic Republic, a top U.S. official said on Tuesday, adding that change in Syria was "inevitable."President Barack Obama's National Security Advisor Tom Donilon, speaking a day after the United States announced new measures against Iran over its nuclear program, said that "end of the Assad regime would constitute Iran’s greatest setback in the region yet—a strategic blow that will further shift the balance of power in the region against Iran." Speaking on the little backing Iran receives in the region, Donilon said that Iran was "basically down to just two principal remaining allies—the Assad clique in Syria and Hezbollah."