First this happens-
Lebanon Government Resigns After Protest
Pressure Mounts on Syria After Lebanon Govt Collapse
One of two things are going happen.
1) The Syrian puppet of a president in Lebanon resigns also, Syria backs off, pulls out troops and all other forms of foreign intrusion. This will weaken an already fragile government in Syria's homeland, causing the same kind of uprising and revolt inside Syria. Voila - two new free nations to W's credit.
2) The Syrian puppet of a president in Lebanon refuses to go, (or maybe even if does) Syria holds a hard line, and we see those WMD's we've been looking for used on the protesters. This galvanic world opinion and we, now knowing about WMDs, liberate Lebanon and topple Syria.
The second option is ugly, complicated, and VERY dangerous. But if either of these happen, the opposition in Iran will follow the Lebanese example. Why do you think that both the Saudi and Egyptian governments have announced free elections in the future. The writing is on the wall.
To get to this point, the President needs to make a very strong statement of support for the Lebanese protesters. The pressure is mounting and all we need to do is provide a small release and watch out.