This year’s Munich Security Conference returned to the theme of great power conflict, which many thought had ended with the cold war almost three decades ago. Against a morbid backdrop of three aircraft — Russian, Turkish and Israeli — being downed over Syria, Wolfgang Ischinger, chairman of this gathering of defence and security policymakers, said that “at no time since the collapse of the Soviet Union has the risk of armed conflict between major powers been as high as it is today”. That seems right. In Syria there is a real risk of clashes between Nato allies Turkey and the US, and between the US and Russia. These can probably be contained through the use of proxies, which was how the US and Soviet Union fought each other across Africa, Asia and Latin America during the cold war. Yet Middle Eastern crises have a habit of ricocheting out of the region. While the cold war balance of nuclear terror obtained, the two sides managed the risks: notably during the 1973 Arab-Israeli war and the 1982 confrontation between Israel and Syria. But in the era of presidents Donald Trump and Vladimir Putin, with everything from diplomatic protocols to deconfliction hotlines in question, it is hard to be optimistic. Two weeks after US air strikes in eastern Syria killed an unknown number of Russian “contractors”, US secretary of defence Jim Mattis confesses to being puzzled about what happened. The Kremlin at first feigned ignorance, but on Tuesday acknowledged Russian citizens were wounded in the incident. In a region of “conflict clusters”, as Joost Hiltermann, Middle East director at International Crisis Group, puts it: “Conflicts within a cluster have started to bleed into conflicts in another cluster; and . . . individual conflicts in the [Middle East] have broadened to suck in, first, regional powers and, then, global actors as a result of power and security vacuums created in the chaos of war”. Moving from the Levant to the Gulf, for instance, what might happen if one of the rockets periodically fired from Yemen into Saudi Arabia by Iran-backed Houthi rebels penetrates the kingdom’s missile shield and causes mass casualties? If the Saudis cannot defeat rag-tag Houthi forces after three years and tens of billions of dollars, they are unlikely to do better against Iran. While Mr Trump, at a summit in Riyadh last May, urged Saudi Arabia to lead the Sunni Arab camp against Shia (and Persian) Iran, the Saudis themselves seem happier for Israel to take the lead. And Israeli prime minister Benjamin Netanyahu’s weekend threat at Munich to act directly against Iran as well as its proxies, to prevent them entrenching themselves in a new frontline in Syria, is a fearful portent of a new war that could turn much of the region into one vast bleeding cluster. Syria’s civil war has enabled Iran, alongside paramilitary allies such as Lebanon’s Hizbollah and with Russian air force support from 2015, both to put down roots and complete a Shia Arab arc through Iraq and Syria to the Mediterranean. Israel, beyond bombing what it says are Iranian arms depots and convoys in Syria destined for Hizbollah, has kept out of this war. But it has been saying for two years that it will launch its own war if either of two things happen: if Iran, Hizbollah and other militias nurtured by Iran’s Revolutionary Guard establish a permanent military presence in Syria, in effect opening a new front against Israel, alongside the Lebanese border to its north; or if Hizbollah, which fought Israel to a standstill in the previous Lebanon war in 2006, continring such a war nearer. The Trump administration in the US is both rudderless and reckless in the Middle East. Yet its national security adviser, HR McMaster, seen by some as a brake on Trumpian excess, told the Munich conference “the time is now, we think, to act against Iran”. Iran, busily replicating Hizbollah in Iraq, Syria and Yemen, is trying to deter Israel (and the Saudis) by warning that it would respond regionally to any attack, but may be over-reaching. Two Iraqi Shia militia leaders have recently visited Beirut and Lebanon’s border with Israel. That was already provocative before an Iranian drone crossed from Syria into Israel, setting in motion the chain of events that led to the downed Israeli aircraft and a blitz of Israeli reprisals. Any more miscalculations could be fatal.