"According to the official, Israel has warned Syria not to allow the transfer of the SA2 missiles into the hands of Hezbollah, and views the transfer of such missiles as the crossing of a red line. " Then Israel would - without question - be the aggressor, because such an attack would be a PREVENTATIVE action, and not a PRE-EMPTIVE action. Int'l law is very clear on that point: you can not attack merely to prevent someone gaining a CAPABILITY to harm you. Look up the "Caroline" case. Look up the "Nicaragua" case. An attack by Israel on Syria over this "threat" would be naked aggression, and nothing more.
from the article: U.S. official: Arming of Hezbollah could spark Israel-Syria war