Since 2011 there has been a civil war in Syria. In recent years Bashar al Assad, with massive support from Iran, Hezbollah and Russia had succeeded in gradually defeating various rebels groups. Israel was not involved in the Syrian war. Israel did give humanitarian aid to more than 3,000 Syrians and also carried out more than 100 air strikes inside Syria, aimed at stopping the deliveries of advanced weapons to Hezbollah. On February 10 and again on April 9, 2018 Israel bombed T4, a military airfield, located deep inside Syria. The goal was to hit the Iranian presence there, as part of the Israeli effort to reduce as much as possible the Iranian military deployment in Syria, before it will be turned against Israel.
On February 10 an Israeli gunship shot down an armed Iranian UAV (Unmanned air vehicle) that infiltrated into the north – east of Israel. Following that Israeli aircraft destroyed the command and control center of that Iranian UAV. The Syrian anti defense had fired 26 antiaircraft missiles, which shot down one Israeli F- 16I. Israel retaliated by launching its biggest attack against the Syrian air defense since 1982. On April 9 Assad’s air defense did not repeat its quite massive antiaircraft fire from February 10, which suggests that Israel had managed to deter Assad in a certain way.
The Iranian presence in Syria imposes a potential danger to Israel. However, the fragile situation there, following the Iranian provocation i.e. sending the UAV, also allows Israel to harm Iran, as part of its conflict with the current regime there. By bombing Iranian forces in Syria, especially after they attack Israel, like by sending armed UAV into Israel, Israel can humiliate Iran. It will have a negative effect on Iran’s status in the Middle East. Furthermore Israel could argue that since Iran attacks Israel from Syria then Israel holds the right to strike Iran itself, like its nuclear facilities. It might be needed if Iran tries to produce a nuclear weapon. Such a scenario might happen if the United States gets out of the agreement that was singed on July 2015, in regard to Iran’s nuclear program.
Israel can also give a strong warning, directly or not, that it will hit Assad, since the Iranian attacks will be launched from Syria, and Israel sees Assad as responsible for whatever takes place in Syria. Iran will not want that Assad will be weakened let alone put in a spot where he might lose his rule, after investing so much in keeping him in power. Such constraint could serve as leverage against Iran.