Yesterday’s exchange of missile and air attacks between Iranian forces stationed in Syria and Israel was the most violent and overt exchange so far between them in their “secret war”. In this shadowy conflict, Tehran is making strenuous efforts to consolidate its military foothold in Syria, gained by being the military savior—along with Russia and with proxy Shiite militias—of the Assad regime, into a permanent presence. The Islamic Republic also hopes to improve its strategic capabilities there, especially surface-to-surface missiles, unmanned aerial vehicles, and air defense. Israel is determined to prevent such an eventuality: Since the beginning of the Syrian Civil War, it has carried out, without taking credit until the last few weeks, over one hundred airstrikes against the Hezbollah and Iranian strategic capabilities in Syria.

The back-and-forth between Israel and Iran has escalated over the course of 2018. In response to Iran dispatching an unmanned aerial vehicle into Israeli airspace on February 10, Israel carried a series of air operations against Iranian targets. Israel’s operations reached their  peak in the April 9 attack on Iranian targets in the T-4 airfield in Syria, which resulted in numerous Iranian casualties; they were uncharacteristically publicized by the Iranian regime. The April 9 attack raised the profile, and the stakes, of the conflict. Netanyahu’s exposé of the intelligence operation inside Iran that brought a secret Iranian archive to Israel, and the ensuing diplomatic and information campaign, only strengthened this vector.

On May 9, according to Israeli military sources, the Quds Force—the external arm of the Islamic Revolutionary Guards under Qassem Suleimani—fired some twenty rockets from Syria at Israeli military outposts on the Golan Heights: three were intercepted by Israel’s missile defense systems, and the others landed in Syrian territory. There were no Israeli casualties. In response, Israel carried out a large-scale strike against the gamut of Iranian targets in Syria and attacked five Syrian air defense targets which had fired on Israeli aircraft. Defense Minister Avigdor Lieberman claimed that the country’s air force had destroyed “nearly all” of Iran’s military infrastructure in Syria; be that as it may, Iran’s forces in Syria seem to have suffered a severe blow.

The U.S., the U.K., France, and Germany backed the Israeli action.

Israel had been anticipating Iran’s reaction to the recent strikes and warned its citizens of the possibility of a limited missile attack on Israeli military targets from Syria or Lebanon. Shelters were opened in some Northern areas of Israel, by decision of the local councils. There has been no special alert status proclaimed nationwide by the Rear Area Command. Senior military sources quoted in the Israeli press spoke of concrete preparations by the Quds Force for a retaliatory salvo from Syrian territory. Israeli strikes over the weekend around Damascus, which preceded yesterday’s exchange, are reported to have been aimed at disrupting this activity.

What will happen next is unclear. The fact that Iran has responded so far in a measured manner, from Syrian territory, and in accordance with Israeli estimates, is illustrative. Iran has much to lose from further escalation with Israel at this juncture. The American withdrawal from the Joint Comprehensive Plan of Action (JCPOA), better known as “the Iran Deal,” has made it even more important for Iran to portray itself as a responsible international actor, committed to international agreements and legitimacy. Doing so would put it in contrast to the internationally unpopular American President, who is already being portrayed as a tool of Israeli interests. In addition, its instruments are limited and somewhat crude: Iran does possess conventional surface-to-surface missiles which could reach Israel from within Iranian territory, but it is unlikely to launch such an attack and risk massive Israeli retaliation against its homeland, especially in view of Israeli missile defense capabilities. Iran could “unleash” its intelligence services and proxy networks worldwide against Israeli and Jewish targets, but such a strategy may well harm the significant international political gains it has achieved in the past three years and play into the hands of the anti-Iranian camp in the international and regional arenas. It can also use cyber attacks.

Yesterday’s barrage was the first time Iranian forces fired directly at Israel. Up until now, it has responded to Israeli actions from Lebanon using Hezbollah or other proxy forces, usually Palestinian. But it appears Hezbollah might not be willing, or able, to take that role after their long, successful but costly engagement in Syria. It is unclear whether it will be willing to fight Iran’s war to the last Lebanese. There still seems to be a fair degree of residual deterrence from the 2006 war with Israel (the degree and robustness of deterrence, of course, can only be measured if and when it fails). In addition, Hezbollah and its allies have just achieved significant gains in the Lebanese elections with a rise in the representation of their allies and decline of support for their arch-rival, Prime Minister and Sunni leader Saad Hariri. Hezbollah appears appear loath to threaten their political position and risk being seen again as those who brought destruction to Lebanon.

Russia—with its radar coverage and air defense in Syria, the presence of embedded Russian advisors in Syrian units, and a “hot-line” with the Israeli Defense Forces to avoid friction between the two air forces operating in close proximity—is undoubtedly aware of much of the Israeli campaign and does not seem to give advance warning to its ostensible allies. In its campaign, Israel takes special care to avoid any threat to Russian forces and has quickly engaged diplomatically with Moscow when inadvertent tensions arose.

An Israeli military spokesman reported that Israel had informed Russia prior to its response strikes against multiple targets in Syria, through the existing mechanisms. Russia may have its own doubts and concerns about the role of Iran in the future of Syria; the close military cooperation in the field was necessary to save Assad, but the Russian calculus may have now changed. Moscow understands that Israel has the ability to disrupt the new strategic architecture and that Russia needs Israel to feel confident about her own national security concerns. Prime Minister Netanyahu paid a visit on very short notice to Moscow on May 9 (and participated alongside Putin in the Victory Day parade), hours after the American announcement of its withdrawal from the JCPOA and immediately before the most recent exchange. Netanyahu  noted after his visit that he has no reason to believe that Russia will restrict Israel’s freedom of action. Israel’s increased willingness to use force against the Iranian presence in Syria may be aimed partly at Moscow. What is happening now may be, inter alia, an attempt to convince or compel the Russians to rein in the Iranians by raising the stakes of their “sitting on the fence” vis-à-vis the stability of the Assad regime and the Russian-constructed status quo ante in Syria.

Israel is determined not to allow the crystallization of new “rules of the game” in Syria, similar to those which have hardened in Lebanon since 2006. There, Hezbollah has, on the one hand, been deterred by the destructive results of the Second Lebanese War—which resulted from their miscalculation of the Israeli threshold for violence—from carrying out attacks or barrages across the border into Israel. On the other hand, it has solidified its de facto control of the Lebanese governing system and of territory near the Israeli-Lebanese border (the “Blue Line”), as well as created of a vast rocket and missile arsenal aimed at Israel. Recent Israeli actions and statements are overt and tacit messaging aimed at influencing Iranian behavior in the direction of greater caution, thereby reducing the possibility of greatly expanded open conflict. Deterrent messages are also aimed at Damascus: Israeli officials have ramped up their statements that if President Assad does not control the Iranian buildup, his regime might be toppled.

There is of course linkage with the Israeli campaign regarding the roll-back of the Iran deal. Jerusalem is concerned about the creeping normalization of the Iranian regime internationally since the nuclear deal. Putting a spotlight on the Iranian threat in Syria, then, serves the greater narrative regarding the need to contain and roll back Iran, and cancel or rewrite the Iran Deal. Some cynical observers link Prime Minister Netanyahu’s recent steps regarding the Iranian issue to a desire to concentrate public attention on external security threats, which in Israeli politics traditionally trump any domestic concerns, rather than on investigations and questions about possible involvement by Netanyahu in dubious activities. Some connect the current atmosphere of crisis to the Knesset’s lightning approval on April 30 of a moribund law transferring responsibility for declaring war from the full government to the smaller security cabinet. In extreme circumstances, the law authorizes the prime minister, in consultation with the defense minister, to make such a decision on their own. While there is less to this than meets the eye—almost all of Israel’s wars have not been accompanied by formal declarations, and the full government is a dysfunctional forum for debating and deciding pressing national security issues—the optics of the timing are both striking in the domestic context and strongly support the deterrent messaging toward Iran.

The era of “all-out,” decisive wars in the region, which solved problems and had clear victors, has passed—if it ever existed. Israel is in the midst of a Thirty Year War with Hezbollah and Iran, as well as with Hamas, characterized by peaks and troughs. We are currently in a warm, peak phase. What happens next is dependent on the interplay of the various parties’ interests and needs, and especially on whether Israeli actions lead to a slowdown in the Iranian encroachment in Syria or to a change in the Russian tolerance towards it, on the one hand, and how Israel will calibrate its next steps, on the other.