The problem with the people that are supporting Assad in this conflict Parham jaan, is that they think the Syrian army and Air force or air defences are a real threat to an Israeli or NATO intervention and that's why these players would be scared of intervening and rather destabilize his regime through a ragtag rebel force! That assertion lacks any type of objectivity if you looks at the decades of the Israeli-Syrian conflict and historical facts. When Israel attacked Syria's undeclared nuclear reactor in 2007, there were reports that the entire Syrian air defence system went down during the attack! If that was a fluke, then how does one explain the last 3 attacks this year. Like you said, they (the Israelis) can hit the presidential palace at will, with great accuracy and without even entering Syrian air space. Theoretically speaking Syria has SAM-5's that can even shoot down planes over Cyprus, so why are they struggling to shoot down a couple of F-16's flying over Lebanon or over the Golan? The answer is that the Israelis know exactly how to jam their outdated Russian air defences any time they want. They simply do not want to take Assad out. They know he's a weak leader and one has not jeopardized their interests - hell, even his father that was more of a military man had no success against Israel. That would not be the case if Al Qaida linked terrorists start operating near the Golan Heights. That would open up a whole new front for Israel in an area that has enjoyed relative calm for decades.