While most analysts agree that the fall of Assad’s regime would remove a reliable ally of Iran, the Islamic Republic might use that power vacuum to forge a closer bridge to Hezbollah or gain sway over a fledgling Syrian ruler. And even the weakening of Assad's rule could give Iran an opportunity to expand its influence in Syria, by propping up Assad.
Israel is also afraid that if Syria’s Sunni majority were to replace the Alawite minority now in charge, it would give the Syrian branch of the Muslim Brotherhood a dominant role in the country. Even if the Sunni leadership were secular, analysts in Israel said they are likely to take even more of a hard line against Israel because of historic ties to Sunni Muslims in the Palestinian territories.
"Assad is definitely an enemy who helps Hamas and Hezbollah. But the disintegration is frightening," says Alon Liel, a former managing director of the Israeli foreign ministry who has advocated in the past for Israel-Syrian peace talks. "There is no one opposition group that can take control of Syria. It’s quite a mess."
Syria's Assad: A stable neighbor