Iran’s unprecedented strikes on Israel this weekend have shaken Israel’s assumptions about its foe, undermining its long-held calculation that Iran would be best deterred by greater Israeli aggression.

For years, Israeli officials have argued, both in public and in private, that the harder Iran is hit, the warier it will be about fighting back. Iran’s barrage of more than 300 drones and missiles on Saturday — the first direct attack by Iran on Israel — has overturned that logic.

The attack was a response to Israel’s strike earlier this month in Syria that killed seven Iranian military officials there. Analysts said it showed that leaders in Tehran are no longer content with battling Israel through their various proxies, like Hezbollah in Lebanon or the Houthis in Yemen, but instead are prepared to take on Israel directly.

“I think we miscalculated,” said Sima Shine, a former head of research for the Mossad, Israel’s foreign intelligence agency.

“The accumulated experience of Israel is that Iran doesn’t have good means to retaliate,” Ms. Shine added. “There was a strong feeling that they don’t want to be involved in the war.”

Instead, Iran has created “a completely new paradigm,” Ms. Shine said.

Iran’s response ultimately caused little damage in Israel, in large part because Iran had telegraphed its intentions well in advance, giving Israel and its allies several days to prepare a strong defense. Iran also released a statement, even before the attack was over, that it had no further plans to strike Israel.

Nevertheless, Iran’s strikes turn a yearslong shadow war between Israel and Iran into a direct confrontation — albeit one that could yet be contained, depending on how Israel responds. Iran has demonstrated that it has considerable firepower that can only be rebuffed with intensive support from Israel’s allies, like the United States, underscoring how much damage it could potentially inflict without such protection.

Iran and Israel once had a more ambiguous relationship, with Israel even selling arms to Iran during the Iran-Iraq war in the 1980s. But their ties later frayed after that war ended; Iranian leaders became increasingly critical of Israel’s approach to the Palestinians, and Israel grew wary of Iran’s efforts to build a nuclear program and its increased support for Hezbollah.

For more than a decade, both countries have quietly targeted each other’s interests across the region, while rarely announcing any individual action.

Iran has supported Hamas and financed and armed other regional militias hostile to Israel, several of which have been engaged in a low-level conflict with Israel since the deadly attacks by Hamas on Oct. 7. Similarly, Israel has regularly targeted those proxies, as well as assassinated Iranian officials, including on Iranian soil, killings for which it avoids taking formal responsibility.

Both countries have targeted merchant ships with links to their opponents, as well as carried out cyberattacks on one another, and Israel has repeatedly sabotaged Iran’s nuclear program.

Now, that war is out in the open. And in large part, it is because of what some analysts see as an Israeli miscalculation on April 1, when Israeli strikes destroyed part of an Iranian embassy complex in Damascus, Syria, one of Iran’s closest allies and proxies, killing the seven Iranian military officials, including three top commanders.

The attack followed repeated suggestions from Israeli leaders that greater pressure on Iran would encourage Tehran to scale back its ambitions across the Middle East. “An increase in the pressure placed on Iran is critical,” Yoav Gallant, Israel’s defense minister, said in January, “and may prevent regional escalation in additional arenas.”

Instead, the Damascus attack led directly to the first Iranian assault on Israeli sovereign territory.

Israel may have misunderstood Iran’s position because of the lack of Iranian response to earlier Israeli assassinations of senior Iranian officials, analysts said.

Though Israeli leaders have long feared that Iran will one day build and fire nuclear missiles at Israel, they had grown used to targeting Iranian officials without direct retaliation from Tehran.

In one of the most brazen attacks, Israel killed Iran’s top nuclear scientist, Mohsen Fakhrizadeh, in 2020 on Iranian soil. As recently as December, Israel was accused of killing a top Iranian general, Sayyed Razi Mousavi, in a strike in Syria, where Iranian military officials advise and support the Syrian government. Those and several other assassinations did not prompt retaliatory Iranian strikes on Israel.

Iran’s decision to respond this time was partly prompted by the fury in some circles of Iranian society at Iran’s previous passivity, according to Ali Vaez, an Iran analyst.

“The degree of bottom-up pressure that I saw on the regime over the past 10 days, I’ve never seen before,” said Mr. Vaez, an analyst at the International Crisis Group, a research group based in Brussels.

Iran also needed to show proxies like Hezbollah that it could stand up for itself, Mr. Vaez added. “To demonstrate that Iran is too afraid to retaliate against such a brazen attack on its own diplomatic facility in Damascus would have been very damaging for Iran’s relations and the credibility of the Iranians in the eyes of their regional partners,” he said.

For some analysts, Israel’s strike on Damascus may yet prove to have been a smaller miscalculation than it first appeared. Iran’s aerial assault has already distracted from Israel’s faltering war against Hamas, and reaffirmed Israel’s ties with Western and Arab allies who had become increasingly critical of Israel’s conduct in Gaza.

The fact that Iran gave Israel so long to prepare for the attack could indicate that Tehran remains relatively deterred, seeking to create only the optics of a major response while trying to avoid a significant escalation, said Michael Koplow, an Israel analyst at the Israel Policy Forum, a research group based in New York.

“To me, the jury is out,” Mr. Koplow said.

“The question is whether this was intended to be something that would actually damage Israel, or if this was supposed to be something that made it seem as though they were responding in strength, but actually signaled that they weren’t,” Mr. Koplow added.

But for others, it was already clear. Aaron David Miller, an analyst at the Carnegie Endowment for International Peace, a Washington-based research group, said that Israel had now made two major strategic errors in less than a year: Before Oct. 7, Israeli officials had publicly — and wrongly — concluded that Hamas had been deterred from attacking Israel.

Then Hamas launched the deadliest attack in Israel’s history.

“When it comes to conceptions, Israel is batting 0 for 2,” said Mr. Miller. “They failed to read Hamas’s capacity and motivation correctly on Oct. 7 and they clearly misjudged how Iran would respond to the April 1 hit.”

Gabby Sobelman contributed reporting.

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