I have a feeling that Syria may be drawn into this sooner or later.
Which could be devastating.
Think about it: Syria is supporting Hezbollah. From time to time Israel even hits targets inside Syria. Let's say that happens, or someone thinks it did, and the Israel/Syria border becomes ugly.
Enter Iran. Iran's President might follow up on his threat and launch missiles (which may or may not be nuclear) at Israel and perhaps Iraq, and invade Iraq intending to 'liberate it' from 'Zionist oppressors'. Boom. Big war, possibly World War Three.
If Iran were to contrubite forces to this how would he even get them to Syria, The only route I can think of is over the Indian ocean through the Horn Of Africia up through Libya then a sharp turn to Syria, thats an air route they could take but it would be too long to bring in convential ground forces quickly.