The most recent clash between Iran and Israel, on May 10, ended badly for Iran: All of the missiles it fired at Israeli military positions were intercepted or landed outside of Israeli territory. In response, Israel struck some 50 Iranians targets in Syria. The results should come as no surprise because Israel is considerably stronger than Iran in the Syrian arena and Tehran's use of its own forces and Shiite militias is predicated on a mistaken conception.
Originally, these forces were sent to Syria to help save the Assad regime and topple Islamic State, and they were aided by Russian air support. Iran, however, had other ideas: to build a long-term presence in Syria that would pose a significant threat to Israel. The Russian warplanes, though, were deployed to help Assad and to safeguard Russian interests in Syria. Thus far, Russia has not helped Iran in its fight against Israel, and it appears it has no intention of doing so. The Iranian and Shiite forces, therefore, were left without adequate air defenses, while the Iranian air force cannot contend with its Israeli counterpart. The Israeli airstrikes, which destroyed Syrian and Iranian air-defense systems, rendered the Iranian and Shiite fighters exposed. This situation isn't likely to change in any substantial manner in the future. After their resounding failure in early May, the Iranians must know they cannot continue on the same path as before, and that Israel has forced it to plot a new course.
Iran now has two main courses of action to choose from – both problematic. The first option is using its most effective card for deterring Israel from further airstrikes: triggering Hezbollah's massive rocket and missile arsenal; and, less likely, helping it by firing missiles at Israel from Iran. If Iran decides to utilize this capability on a significant scale, it's reasonable to assume Hezbollah will follow orders.
This option, however, comes with two severe risks. First, Israel has repeatedly clarified that missile barrages from Hezbollah will lead to a particularly harsh Israeli response – not just against Hezbollah but all of Lebanon. The second risk is even more profound: Even if Hezbollah fires missiles, Israel will still hold Iran responsible. Israel can retaliate with a concentrated campaign to dislodge the Iranian foothold in Syria and Lebanon, which if successful would ultimately remove Iran from those countries. Even if the Iranians restrict their barrage to military targets, the most recent clash should inform them that even limited rocket fire can provoke a massive Israeli response, and moreover – that activating Hezbollah's missile arsenal on any significant scale means war with Israel. Iran has no interest in getting dragged into a wide-scale conflict because its involvement in Syria places it at a disadvantage. A war with Israel would hamper Iran's attempts to solidify its influence in Syria as well as Iraq and Lebanon. Above all, Israel could see an Iranian provocation as justification for an attack on Iran's nuclear sites.
Iran's other option is to switch into a lower gear when it comes to Israel. Iran won't forgo its intent to raise a flag in Syria, which is its top strategic priority. But in light of the threat that the Iranian foothold in Syria presents to Israel, even though Iran does not have the capability of going to war with Israel on that particular state, Iran might prefer not to make the situation worse. What's more, the Trump administration now comprises an unprecedented threat to Iran, under which Iran can use other methods to bolster its status in Syria, such as economic investment, tighter political ties, and helping build up the Shiite militias in Syria. This does not mean that Iran will give up on military action, just that it will leave out the elements that will pose a challenge to Israel before it has a proper response.
It's hard to know which route Iran will opt for. There could be a debate between the radical arm of the regime and the moderates, which is reflected in President Hassan Rouhani's remarks that Iran does not want more tension and in the calls by the protesters who flooded the streets at the end of 2017 for Iran to stop its costly intervention in Syria.
