If Iran’s clerical regime collapses, Israel will face one of its most consequential strategic moments since 1979. The instinct – particularly outside the Middle East – will be to celebrate and assume that moderation follows. Israel cannot afford that luxury. The real question will not be whether the mullahs are gone, but what replaces them – and how quickly Israel adapts.
To prepare wisely, Israelis should remember something that now feels almost implausible: Israel and Iran were once quiet partners. Under Shah Mohammad Reza Pahlavi, the two countries maintained a pragmatic, largely clandestine relationship rooted in shared interests – opposition to radical Arab nationalism, concern about Soviet penetration of the region, and Israel’s “periphery strategy” of forging ties with non-Arab states on the Middle East’s margins. This was not symbolic diplomacy: It was strategic cooperation.
For years, Iran served as Israel’s primary oil supplier, providing the vast majority of Israel’s crude needs. That relationship culminated in a joint venture established in 1968 to transport Iranian oil from Eilat to Ashkelon for export to Europe. The arrangement benefited both sides: Jerusalem secured energy independence, while Tehran gained a discreet export route bypassing hostile Arab states.
When the Islamic Revolution erupted in 1979, however, the partnership did not merely dissolve – it exploded into secrecy and litigation. Israel nationalized the pipeline assets, and decades later, international arbitration ruled that it owed Iran roughly $1.1 billion plus interest, a lingering financial echo of a relationship many now forget ever existed.
The cooperation extended beyond oil. Israeli and Iranian intelligence services collaborated on regional security matters, including shared concerns over Iraq. Even more striking, in the late 1970s, the two countries engaged in a covert missile-development effort – known as Project Flower – part of an oil-for-arms framework documented in declassified US records.
None of this is nostalgia. It is a reminder that Iran is not historically destined to be Israel’s ideological enemy. It is also a warning: Relationships built on interests can collapse overnight when ideology captures the state.
If the Islamic Republic falls, Israel’s challenge will not be to chase peace fantasies, but to avoid strategic surprise.
One possibility is the emergence of a pragmatic nationalist government seeking sanctions relief, foreign investment, and international legitimacy. Such a regime would not suddenly become pro-Israel, but it might decide that exporting revolution and financing proxies is economically ruinous. For Israel, this could translate into reduced pressure on its borders and quieter regional behavior, even without formal ties.
Another scenario is consolidation of power under Iran’s military or remnants of its Revolutionary Guard. This outcome may disappoint those expecting liberalization. A unified Iran could abandon clerical ideology while retaining missile programs, regional ambitions, and hostility toward Israel as a unifying narrative. In such a case, deterrence – not optimism – would remain Israel’s primary strategic tool.
Israel could face short-term danger
The most dangerous possibility, however, is fragmentation. A collapsing center could unleash internal conflict, ethnic separatism, and competition over strategic assets. Missiles, drones, and nuclear expertise could leak to proxies or foreign patrons. In this scenario, Israel could face heightened short-term danger even as the regime weakens.
There is also the risk of a revolution that looks different but where its actors behave the same. History offers many examples of regimes that rebrand while preserving core strategic goals; smiles for Western cameras would not necessarily mean an end to enrichment, proxy warfare, or regional destabilization.
Israel cannot shape Iran’s internal future, but it can shape its own readiness. That begins with developing a serious “day after Iran” doctrine – one treated with the same rigor as war planning. This means interagency coordination on nuclear-site security, proxy disruption, border instability, and rapid diplomatic positioning.
It also requires consistently separating the Iranian people from their rulers. This is not mere rhetoric: A post-clerical Iran will remember who spoke to its citizens with respect and who treated the entire nation as irredeemable.
Discrete channels – through allies and intermediaries – should be prepared now, not improvised later. Israel may not be first in line for formal engagement, but it must be positioned to prevent miscalculations during a volatile transition. At the same time, optimism must not weaken red lines. Transitional periods are when oversight collapses, records disappear, and dangerous materials move. Instability is not a peace dividend; it is a proliferation risk.
The Islamic Republic conditioned Israelis to see Iran as a permanent enemy. The Shah era teaches a more complicated lesson: Iranian ruling ideologies can change faster than geography, and interests realign. But the moment of transition – when old restraints vanish, and new rules are unwritten – is when danger peaks.
If the mullahs fall, Israel should hope for a better Iran. But hope is not a strategy: Preparation is. Because the day after Tehran will not automatically be the day of peace. It will be the day Israel must prove that it has understood history – and learned from it.
The writer is an attorney and the father of Alisa Flatow, who was murdered in an Iranian-sponsored Palestinian terrorist attack in 1995. He is author of A Father’s Story: My Fight for Justice Against Iranian Terror and is president of the Religious Zionists of America-Mizrachi. An oleh chadash (new immigrant), he lives in Jerusalem.