Assessing Israel’s Strike on Iran

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The dangerous back-and-forth between Israel and Iran appeared to end—at least for now—on April 19 when Israel destroyed part of an S-300 long-range air defense system in Isfahan, Iran. Based on the authors’ analysis of the attack, Israel walked a tightrope between escalating the conflict further and inaction, while also signaling to Tehran that it could conduct precision strikes against strategic locations—such as Iran’s Natanz nuclear enrichment facility and its broader air defense system.

An Israeli attack on a diplomatic facility in Damascus that killed seven Islamic Revolutionary Guard Corps (IRGC) officers on April 1 triggered the crisis. Iranian leaders probably felt the need to show their domestic population and elites that the country could not be attacked with impunity. Iran responded with a barrage of more than 300 missiles and drones on April 13, the first direct attack ever launched against Israel from Iranian soil.

Given the scale and unprecedented nature of Iran’s attack, the Israeli response seems small. But the April 19 attack is best understood as a calibrated attempt to deter Iran while avoiding escalation. Israel’s response carried a clear threat against Iran’s most sensitive political and military targets, particularly its nuclear infrastructure, while avoiding key triggers for further escalation. The design of the strike suggests that Israel wants to avoid war with Iran, just as Iran is signaling that it does not seek war with Israel.

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Although it lacked the scale of Iran’s bombardment, Israel’s response was menacing in a different way, serving as an implicit threat against Iran’s most important military capabilities—particularly its nuclear infrastructure. The S-300 is Iran’s most advanced air defense system and is permanently deployed at Iran’s most important military and political sites. S-300 batteries are located in Tehran, Bandar-e Bushehr, and Isfahan according to a Defense Intelligence Agency assessment.

Tehran is of course Iran’s capital, while Bandar-e Bushehr holds an important naval facility, an airbase, and major energy infrastructure. Isfahan is also the location of an airbase, but it more importantly lies approximately 100 kilometers south of the Natanz enrichment complex and 20 kilometers north of the Isfahan Nuclear Technology Center, two sites at the core of Iran’s nuclear program. Given the central importance of Iran’s nuclear program to both Tehran and Tel Aviv, the strike probably conveyed a threat.

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At the same time, Israel appears to have little interest in a broader regional war. A larger strike that caused significant damage or resulted in many casualties might have forced Iranian leaders to prove to their own people and to the many IRGC veterans in political leadership that Iran would strike back. 

The damage at Isfahan was sufficiently small scale to prevent such political outrage. The attack probably destroyed only a single 30N6 Flap Lid or 30N6E Tomb Stone engagement radar. While this represents greater damage than Israel suffered on April 13, the system is replaceable. Satellite imagery shows damage to the site where an engagement radar usually sits. But Iran appeared to have replaced the damaged radar within a day of the attack, although commercial satellite imagery is insufficient to determine whether the system is operational or whether Iran replaced the engagement radar with a 96L6E Cheese Board early warning and acquisition radar that would leave the site nonoperational while allowing Tehran to claim that the attack did no damage.

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The attack could also have escalated the conflict if Iran feared that the strike was part of a larger operation. Even though Israel kept its strike small, Iran might have feared the attack against its air defense infrastructure could have been a prelude to more consequential strikes against its military or political infrastructure. If Tehran believed that such an attack was underway, it would have faced pressure to launch its own strikes before its missiles or aircraft were destroyed on the ground.

The strike minimized this fear by targeting only the shortest-range radar in Iran’s air defense complex, designed not to locate threats but to guide interceptor missiles to their target. Although the system would be ineffective until a new engagement radar was installed, Iran would also have maintained relatively high confidence that the sky above Natanz was not about to be full of Israeli jets.

Finally, the attack might have led to further escalation and war if Iran believed it crossed a new symbolic threshold that forced Tehran to escalate in response. But the attack avoided this escalation by replicating the visible features of previous attacks against military facilities in Iran, which were likely conducted with quadcopter drones, and by striking military rather than civilian targets. Some evidence suggests that this time Israel struck Iran with a missile launched from Syrian airspace, but Iranian leaders do not seem to believe that the attack was sufficiently different as to require a response that would risk open war. Iranian media claimed that air defenses had destroyed three drones over Isfahan and made no mention of a missile.

The level of calibration apparent in Israel’s strike suggests that Israel still wants to avoid open war with Iran, matching Iran’s signaling that it does not want open war with Israel. But this new status quo is hardly guaranteed to hold. For example, changes in domestic politics could make both countries more willing to risk war. Israeli prime minister Benjamin Netanyahu seems to have gained international and domestic support for his measured response, but war cabinet members Benny Gantz and Gadi Eisenkot argued for a counterattack while Iranian drones and missiles were still in the sky over Israel on April 13. In addition, far-right national security minister Itamar Ben-Gvir called on Israel to “go berserk” and deliver “a crushing attack” in response to Iran’s bombardment before suggesting that Israel’s response was insufficient. While Iran’s politics are more opaque, there are almost certainly hard-liners pressing for more open action against Israel.

Even though both sides stepped back from the brink, the Middle East is a more dangerous place because of April’s crisis. Both Israel and Iran crossed important symbolic thresholds, and both parties could be more willing to escalate to comparable attacks in the future. And there will be plenty of opportunities for them to do so. Israel appears to be gearing up for an invasion of Rafah, its conflict with Hezbollah in Lebanon continues to rage, and Iranian-backed groups still conduct attacks across the region. With its airstrike, however, Israel appears to have successfully walked a tightrope between escalation and inaction.

Alexander Palmer is an associate fellow with the Transnational Threats Project at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Daniel Byman is a senior fellow with the Transnational Threats Project at CSIS. Seth G. Jones is senior vice president, Harold Brown Chair, director of the International Security Program, and director of the Transnational Threats Project at CSIS. Joseph S. Bermudez Jr. is a senior fellow for imagery analysis with the iDeas Lab and Korea Chair at CSIS.

Special thanks to William Taylor in the CSIS iDeas Lab for imagery markup design and to Katherine Stark for editing and publication support.

Daniel Byman
Senior Fellow, Transnational Threats Project
Seth G. Jones
Senior Vice President; Harold Brown Chair; and Director, International Security Program