The huge explosion that destroyed much of central Beirut is a daunting metaphor for the perils facing failing Middle East states. For years, the region has been described as the world’s most unstable, as a powder-keg primed to detonate at any moment. Last week’s awful tragedy begs a bigger question about how many shocks such fragile, vulnerable countries can absorb before they fracture, crash and blast apart. Is the Middle East as a whole about to explode? Nearly 10 years after the Arab spring’s hopes of reform were dashed in a storm of violence and counter-revolution, and at a time when regional tensions are again approaching boiling point, a possible watershed nears. As Thursday’s visit by French president Emmanuel Macron and global offers of assistance suggest, the world is suddenly paying renewed attention. Perhaps this will supply a wider impetus for the sort of fundamental changes many in Lebanon and neighbouring countries now angrily demand. By many measures, the Lebanese republic, founded in 1943 at the close of the French Mandate, was already in existential crisis. A failed state is defined as one unable to protect, feed and employ its people, defend its borders or pay its debts. Lebanon meets all these criteria. The official negligence that allegedly caused Tuesday’s disaster is typically a product of governance systems hollowed out by factionalism, sectarianism, corruption and lack of democratic accountability. Again, the Beirut government ticks the boxes. Yet of all these many ills, the blight of foreign interference is perhaps the most pernicious – and Lebanon is a prime victim. The 1975-1990 civil war left a legacy of division and territorial occupation by Israeli and Syrian forces. It was ill-equipped to deal with large Palestinian and Syrian refugee influxes. Its economic well-being depends on the kindness, or self-interest, of strangers. Power-sharing Lebanese leaders, more confessional than professional, pick sides between the US, the Saudis, Iran and its local Shia ally, Hezbollah. Lebanon is regularly buffeted by skirmishing between Israeli forces and the Islamist militia. No surprise, then, that many in Beirut initially assumed Tuesday’s explosion was caused by an Israeli air strike. In 2017, then Sunni prime minister, Saad Hariri, was abducted and forced to resign by the Saudi regime. Right now, Lebanon’s economy faces fresh damage from US sanctions aimed at Syria and delays to a $20bn IMF bailout dictated by a foreign agenda. In the decade following the Arab spring, regional interventions and manipulation by multiple outside actors have intensified. Oddly, this process has been accelerated by the gradual disengagement of the biggest meddler of all. The US has left a vacuum others compete to fill. If Lebanon cracks under present strains, or descends into renewed civil strife, incessant foreign meddling and string-pulling will be greatly to blame. A disturbingly similar picture is seen in Iraq where a new prime minister, Mustafa al-Kadhimi, is struggling to shake off the twin legacies of American military intervention and regional power-games involving Iran, Turkey and the Gulf Arabs. Kadhimi has called for early elections in response to protesters who, like their Lebanese counterparts, rose up last year in huge numbers to demand a wholesale dismantling of the political system. Sectarian rivalries between Sunni and Shia parties and affiliated militias, corruption, and economic pain, exacerbated in Iraq’s case by falling oil revenues and failure to invest in jobs and infrastructure, also feed instability. But so, too, do foreign states. The Iran-backed Kata’ib Hezbollah militia is blamed for recent attacks on residual US forces fighting Isis. Iran itself is determined to maintain the dominant influence it gained during the chaos following the US invasion. Like his post-2003 predecessors, Kadhimi faces an uphill struggle to save Iraq’s dysfunctional democracy from collapse – and with it, the Iraqi state. His plan for early polls could yet be thwarted in parliament. His attempts to loosen Tehran’s grip have not been helped by cuts in US financial aid. And his personal safety may be at risk after last month’s assassination of a top counter-terrorism adviser, Hisham al-Hashimi. Iraq has already broken apart, in the sense that the de facto autonomous, Kurdish-controlled northern region barely answers to Baghdad. A key player here is Turkey, which has exploited Iraq’s sovereign weakness, ostensibly in pursuit of a vendetta against Kurdish PKK separatists. With his armed interventions in Iraq, Syria and Libya, Recep Tayyip Erdogan, Turkey’s president, recalls the Ottoman sultans of old: imperious, reckless, vicious. What holds true for Lebanon and Iraq holds true across large swathes of the Middle East. Syria is held together only by the limitless brutality of the Assad regime, abetted by another neo-imperialist predator, Russia’s Vladimir Putin. Yet Idlib province remains defiant and there are signs of renewed opposition elsewhere. Whether the Syrian state will survive intact is still an open question. Foreign meddling is also central to Libya’s endless agony, where Russia, Egypt, Saudi Arabia and the UAE have lined up against Turkey, Qatar and Islamist groups. The fact Britain, France and Italy have been sidelined from this oil-fired feeding frenzy speaks to a bigger shift. The old colonial powers who set the rules and drew the borders a century ago have given way to a new generation of oppressors and exploiters. Selfish motives and ruthless methods are the same. Only the names have changed. This oscillating arc of deepening instability includes Yemen, a defenceless failed state and bloody playground for rivalrous regional powers. Could vulnerable Jordan be next? Or might Iran, a country comprising myriad religious and ethnic groups, finally break asunder, succumbing to the relentless hostility of its enemies? This latest fragmentation of the post-1918 Middle East order is no less dangerous because it’s familiar. Expect more explosions. As Beirut picks up the pieces, things could fall apart.