JERUSALEM – The low-boil conflict between Israel and Iran has shaped the Middle East for decades.

       Of the many conflicts that have roiled the region, theirs has long been among the most explosive.

       The two have attacked each other – mostly quietly and, in Iran’s case, often by proxy – while avoiding an escalation into direct war.

       The conflict entered a dangerous new phase with the outbreak of the current war between Israel and the Palestinian group Hamas, which Iran supports.

       That fight has drawn in other Iran-backed militant groups as well as Iran itself.

       Tensions increased after Hamas political chief Ismail Haniyeh was killed in July while visiting Iran, presumably by Israel.

       Then in late September, Israeli forces assassinated the leader of Hezbollah, Iran’s most prized regional ally, and moved into southern Lebanon as part of a campaign against the militia.

       On Oct 1, Iran fired roughly 200 missiles directly at the country in a major escalation. In retaliation, Israel began airstrikes on targets across Iran in the early hours of Oct 26.

       Israel and Iran were allies starting in the 1950s during the reign of Iran’s last monarch, Shah Mohammad Reza Pahlavi, but the friendship abruptly ended with the Islamic revolution in Iran in 1979.

       The country’s new leaders adopted a strong anti-Israel stance, decrying the Jewish state as an imperialist power in the Middle East.

       Iran has supported groups that regularly fight Israel, notably Hamas, Hezbollah and the Houthi rebels, all of which the US considers terrorist organisations.

       Israel regards Iran’s potential to build nuclear weapons as a threat to its existence and is thought to be behind a campaign of sabotage against the country’s atomic programme.

       Iran’s leaders say they have no ambition to build nuclear weapons. The Israelis point to a cache of documents their intelligence agents spirited out of Iran in 2018 that suggests otherwise.

       Israeli officials have repeatedly implied that if Iran were to reach the brink of weapons capability, they would attack its nuclear programme using air power, as they did Iraq’s in 1981 and Syria’s in 2007.

       Lebanon is the oldest front in the shadow war.

       In reaction to Israel’s invasion of the country’s south in 1982, a militia that would become Hezbollah was formed by Lebanese Muslims belonging to the Shiite branch of Islam dominant in Iran.

       Their group to some extent became a proxy for Iran’s premier security force, the Islamic Revolutionary Guard Corps.

       Israel and Hezbollah have fought repeatedly, including in a war in 2006.

       Since Hamas attacked Israel from the Gaza Strip on Oct 7, 2023 provoking the current war, Hezbollah has expressed solidarity with Hamas by firing missiles, mortars and rockets into Israel almost daily, prompting Israel to respond with its own fire.

       With its significant fighting force and arsenal, which includes long-range and precision-guided missiles, Hezbollah is considered to be the most precious asset Iran has for projecting influence in the Middle East.

       Through the course of Syria’s civil war, Iran has built up a military presence in that country.

       It has done so both to support its ally, President Bashar al-Assad, and to assist Hezbollah by creating a land bridge to transfer weaponry from Iran via Iraq and Syria.

       For Israel, this has created a second hostile presence on its northern border beyond Hezbollah’s.

       In an effort to counter it and to stop the arms flow, Israel for years has carried out strikes inside Syria against arms shipments and other targets it says are linked to Iran and its allies, in some cases killing Iranians, according to media reports.

       Strikes on Iranian targets in Syria attributed to Israel accelerated after Oct 7.

       Tit-for-tat attacks on commercial vessels began in 2019.

       Although neither Israel nor Iran has accepted responsibility for the hits on ships connected to the other, they are widely thought to be behind them.

       Targets have included Iranian tankers carrying oil destined for Syria; an Iranian ship off the coast of Yemen that served as a floating base for the Revolutionary Guards; and cargo ships belonging to or linked to Israelis.

       In an escalation of the sea battles, Yemen’s Houthi rebels have disrupted shipping in the Red Sea by attacking ships in a show of solidarity with Hamas.

       They say they are targeting vessels connected to Israel, as well as the US and UK, which have launched retaliatory strikes on Houthi targets.

       But ships with no such ties have been hit.

       The Houthis, who’ve controlled north-western Yemen since civil war broke out in 2014, also have been flinging missiles and drones at Israel.

       Most have been intercepted, but a Houthi drone killed a man in Tel Aviv in July. Israel has launched retaliatory airstrikes on Yemen.

       Accusing separatist groups in Iraq’s autonomous Kurdistan region of collaborating with foreign security services against it, Iran has launched multiple attacks in the region since late 2022.

       Israel has in the past used facilities in northern Iraq to gather intelligence on Iran, according to multiple reports.

       Israel and Iran for the first time exchanged fire on each other’s homelands earlier in 2024.

       Iran launched a massive missile and drone attack on Israel on April 13. It was precipitated by an airstrike two weeks earlier on Iran’s diplomatic buildings in the Syrian capital, Damascus, that was widely attributed to, but not acknowledged by, Israel.

       The strike killed seven Iranian military personnel, including a top commander of the Revolutionary Guard.

       Iran’s attack provoked a more limited return assault by Israel on April 19.

       The barrages caused minimal damage, but they created the precedent for overt, direct fighting between the two countries.

       Then came the exchanges in October.

       In the past, Iran had mostly absorbed Israeli strikes on its interests in Syria.

       In one exception, its forces there in 2018 fired a barrage of missiles toward Israeli positions in the Golan Heights, a plateau Israel captured from Syria in the 1967 war and later annexed. Israel replied with a much greater show of force.

       Covert attacks in the two homelands have been more common.

       Both Iran and Hamas accuse Israel of being responsible for the July 31 killing in Tehran of the Hamas chief Haniyeh.

       Israel is widely thought to be behind the assassination in Tehran of five Iranian nuclear scientists since 2010 and several attacks on nuclear sites inside Iran.

       More than a decade ago, malware known as Stuxnet compromised operations at an Iranian nuclear enrichment facility in what’s suspected to have been a US and Israeli operation.

       In October 2021, an Iranian general said Israel was likely behind a cyber attack that paralysed gas stations across Iran.

       And in January 2023, after an Iranian ammunition depot near the central city of Isfahan was attacked in a drone strike, two US newspapers reported that Israel was responsible.

       Cyber attacks launched by Iran include a hack that sought to cripple computers and water flow for two Israeli districts, according to the Council on Foreign Relations.

       Israel’s forces have a vast technological edge over Iran’s.

       That’s partly down to military and financial support from the US, which has long sought to ensure Israel’s advantage as part of its commitment to the Jewish state’s security.

       For example, Israel is the only state in the Middle East so far that’s bought Lockheed Martin’s F-35 fighter jet – the costliest weapons system ever.

       Israel is also widely believed to have nuclear weapons, though it has never acknowledged that capability.

       Iran has accumulated enough enriched uranium to construct several nuclear bombs should its leaders choose to purify the heavy metal to the 90 per cent level typically used in such weapons.

       It would still have to master the process of weaponising the fuel in order to produce an operable device capable of hitting a remote target.

       Sanctions and political isolation have hobbled Iran’s access to foreign military technology, driving it to develop its own weapons, including the missiles and drones it fired against Israel in April.

       Iran’s combat aircraft are mostly older models, inherited from before the country’s 1979 revolution.

       The country hopes to upgrade its military capabilities through an escalating collaboration with Russia.

       So far, the high-end Russian military items Iran wants most, including Sukhoi Su-35 fighter jets, remain on its wishlist.

       Though at a technological disadvantage, Iran’s military is thought to have a significant stockpile of the ballistic and cruise missiles and cheap unmanned aerial vehicles, or drones, that it deployed against Israel in April.

       As Iran learned in that attack and the subsequent one Oct 1, penetrating Israel’s substantial air defences is a challenge.

       There’s getting past Israeli Air Force fighters. Then there are Israel’s Arrow and David’s Sling air-defence systems, plus the interception capabilities of US and other allied forces in the region.

       Iran’s own defensive arsenal includes surface-to-air missile systems including Russia’s S-300 to counter aircraft and cruise missiles and the locally made Arman anti-ballistic missile system.

       These aren’t nearly as battle tested as Israel’s defences – a testament to Iran’s preference for asymmetric warfare, where it can project out-sized power, over head-to-head combat. BLOOMBERG