Most Viable Response From Syria

Supporting an Insurgency is the most likely response....

Militarily Assad would get slapped hard deal a bit of damage to IDF but overall would lose the beauty of Israel attacking Syria would be the use of land by any other foreign forces allied with Israel (NATO Forces) E.G US forces attacking from Jordan, would be seen to the rest of the Arab would as Working hand in hand with the enemy Israel so Israel can't effectively go into Syria without any backlash on western troops......

So the most likely movement into Syria will be more from backing via weapons and funding the FSA......

The reason Scuds were made a main target in the 1st Gulf war was to keep Israel from entering Iraq after a Scud was launched at Tel-Aviv, if Israel retaliated the coalition forces in Saudi Arabia would have been in jeopardy As they were stationed in Saudi Arabia and this would be seen as Israel working with Coalition troops who are stationed on Arab soil then Saudi Arabia would have been seen as working with the Enemy.