How Israel and Iran went from ‘best friends’ to arch-enemies on the cusp of all-out war

When Ayatollah Ruhollah Khomeini launched an Islamic revolution in Iran in 1979 and overthrew the country’s pro-Western leader, one of the first things he did was cut ties with Israel.

The two countries had been allies under Shah Mohammad Reza Pahlavi, back when the nascent state of Israel was keen to work with any non-Arab friends in the region.

In the 1960s and 1970s, Israel sent contractors and military advisers to Tehran and bought Iranian oil. The two countries were even involved in a joint weapons development programme that was kept under wraps for fear of angering Iran’s Arab allies.

But everything changed when Khomeini, a Shia cleric, seized power. He saw Israel as an American puppet crushing the rights of the Muslim Palestinians, and denied the country had a right to exist.

He gave away the newly evacuated Israeli embassy in Tehran to the Palestinian Liberation Organisation and brought in a new annual holiday, Quds [the Arabic name for Jerusalem] Day, to inspire Muslims around the world to rally against “the usurper Israel”.

“Iran’s post-revolution foreign policy was at first overzealous and ideological: The very existence of Israel was an affront to the anti-imperialist fervour that had captured the Iranian revolutionary psyche,” Dalia Dassa Kaye wrote in the 2011 book Israel and Iran: A Dangerous Rivalry.

In the 1980s and 1990s, Tehran’s enmity towards Israel remained largely rhetorical. Iran would refer publicly to Israel as “Little Satan”, while “Big Satan” was the US.

The Shia-majority country would regularly threaten to destroy Israel in order to save holy Muslim sites such as the Al-Aqsa mosque in Jerusalem, as it tried to paint itself as a key backer of the Palestinian resistance to win support in the Islamic world, which is largely Sunni.

But there were no direct clashes. In fact, Khomeini’s regime ended up buying weapons costing $500 million from the Israeli government during the 1980s Iran-Iraq war to stave off Saddam Hussein’s invading forces.

Proxies waged decades-long shadow war

Meanwhile, however, Iran was building up an army of proxy forces on Israel’s borders – setting up a key precedent in what would become a decades-long shadow war.

Iran was instrumental in helping to transform Shia Lebanese militant group Hezbollah from what the IDF described as “rag-tag group” in the 1980s to the capable military force it is today.

Hezbollah fighters have been travelling to Iran for years for training and Tehran gave the group some $700 million in cash and weapons in 2020 alone, according to a US State Department report.

After the first intifada  – Palestinian uprising – ended in 1993, Iran and Hezbollah hosted fighters of an emerging terror movement called Hamas and taught them how to build and use suicide bombs. The tactic was  exported to Israel and used to deadly effect during the second intifada in the early 2000s.

Since then, Iran is believed to have sent dozens of millions of dollars to Hamas, a predominantly Sunni organisation but one that also denies Israel’s right to exist.

Tehran has also propped up the Syrian regime of Bashar al-Assad and the Houthis in Yemen, both of whom agitate against Israel and Western interests.

Israel did not begin to view Iran as a strategic threat until well into the 1990s. Nobel Peace Prize-winning Prime Minister Yitzhak Rabin once called Iran one of Israel’s “best friends”.

But within a few years he had changed his tone, describing Khomeini as leading a “dark, murderous regime”.

Despite the fact the countries share no border and are more than 1,000 miles away from each other, Iran’s alleged pursuit of nuclear weapons meant that Israel soon had to take Tehran’s threats much more seriously.

Iran has played nuclear catch-up

Israel is widely believed to have possessed nuclear weapons since the late 1960s, despite never having officially acknowledged their existence.

Ever since then, Iran has been playing catch-up, although it has always maintained that its programme is strictly for civilian purposes.

Iran’s nuclear programme first came to light in early 2000s when several Iranian dissident groups revealed the existence of an uranium enrichment site and a heavy-water production facility.

While both can be used for power generation, they can also be repurposed to make weapons-grade uranium and weapons-grade plutonium, raising suspicions that Iran was trying to make a nuclear bomb.

Suspicions were raised further when the US administration announced the discovery of a second, clandestine underground facility to enrich uranium.

In a clear sign of what exactly Israel considered to be an existential threat, suspected Mossad agents carried out a string of attacks on nuclear scientists inside Iran in the early 2010s. In just two years, five prominent physicists were shot dead or killed in car bombs.

Israel also reportedly developed an advanced computer worm that managed to damage centrifuges at one of Iran’s enrichment plans.

In response, Iran targeted several Israeli embassies abroad with car bombs.

After the eight-year rule of Holocaust-denying Iranian president Mahmoud Ahmadinejad finally came to an end in 2013, Iran struck a historic nuclear deal with the West in 2015.

It agreed to significant restrictions on its nuclear programme in exchange for sanctions relief and allowed international monitors to visit some – though not all – of its enrichment sites.

Netanyahu blasted West’s nuclear deal with Iran

Israel was furious, with Benjamin Netanyahu, then in the second of his three periods as prime minister, blasting the agreement for “fuelling Iran’s aggression with hundreds of billions of dollars in sanctions relief”.

Donald Trump withdrew the United States from the deal in 2018, claiming it failed to curtail Iran’s missile programme and regional influence. Tehran began ignoring the restrictions on its nuclear programme a year later.

Since then, Israel is believed to have continued to eliminate top Iranian officials.

When the US assassinated Iranian military commander Qassim Soleimani in January 2020, it was reported to have been done with the help of Israeli intelligence.

In November that year, a remote-controlled gun killed Mohsen Fakhrizadeh, Iran’s top nuclear scientist.

In 2022, seven officers affiliated with Iran’s Islamic Revolutionary Guard Corps (IRGC), including two colonels, were killed in separate incidents.

Since Oct 7, when Hamas launched its brutal assault on Israel and killed around 1,200 people, Israel is alleged to have conducted dozens of strikes in Syria to kill senior Iranian commanders and officials, including the IRGC’s intelligence chief in the country.

This month, it is believed to have bombed Tehran’s embassy in Damascus, wiping out seven Iranians including Mohammad Reza Zahedi, one of the IRGC’s most senior commanders.

But there was a fear the embassy attack could signal a shift in Israel’s long-held strategy of dealing with Iran in a “low-intensity, integrated and preemptive warfare”, Yossi Mekelberg of Chatham House’s Middle East and North Africa programme, wrote in a recent piece.

“There is a real danger of war by miscalculation, as every move by any of the actors involved is perceived as part of a grand plan for eliminating the other side.”

Iran last week launched an unprecedented strike on Israel, in a barrage of more than 350 drones and missiles.

And now, despite warnings from President Biden, it appears Mr Netanyahu has exercised his right to strike Iran at a “manner and time” of Israel’s choosing.

In the early hours of Friday morning, Israel launches what appeared to be a retaliatory strike on Iran, as several drones attacked the Isfahan air base.

The world is now waiting anxiously as the region tips closer to all-out war.