With the decision he made late January 2 to kill the head of the Iranian “Qods Force”, Lt.-Gen Qasem al-Soleimani, Pres. Donald Trump set the United States on a course to an upheaval– certainly political and possibly also military– of truly global impact. The first reverberations of the heightened U.S.-Iran tensions have already been felt in the international oil market and within Iraq. In Iraq, the parliament has voted to expel the U.S. troop presence and the Pentagon has declared the suspension of the anti-ISIS campaign that was their original mission there.

But the political fallout from Trump’s kill order will extend far wider than Iraq. It will spark an upheaval of the global power dynamic throughout the Middle East, and globally. (And that will happen even if an outright US-Iranian shooting war is averted.)

For starters, in response to the Pentagon’s notice about ISIS– which retains a considerable potential to wreak havoc in Iraq, and also some in Syria–there have been reports from Iraq that China has offered to step in to replace the US troops, and speculation that Russia will offer to do so, too. (Russia’s military is already a significant part of the anti-ISIS efforts in Syria.)

It would not be a simple or speedy matter for the US military presence in Iraq to be replaced by those of China or Russia. More on that below. But the fact that such a foreign-military replacement scenario is even being discussed in Iraq marks a clean break from the situation that has prevailed there since the U.S. invasion of 2003. If it comes about, it would mark a sea-change for the region and for the global power balance.

Negotiating and implementing any change on the ground in Iraq will likely take some time. But already, this week, the U.N. Security Council will be addressing the numerous issues stemming from Soleimani’s killing. The Russian and Chinese foreign ministers have already held a phone call in which they agreed that the killing was unlawful and escalatory and agreed to coordinate closely at the Security Council. (One issue around the holding of an SC meeting on the current crisis is that Iran’s foreign minister, Javad Zarif, is now on a US sanctions list that prevents him getting a U.S. visa. Moving the SC discussion to Geneva could be an option?)

It is not clear yet what kind of a resolution the SC’s members, including its veto-wielding permanent members–China, Russia, France, the United States, and the United Kingdom–might propose, though declaring an intention to continue fighting ISIS is almost a given. Outside the SC’s rarefied halls, the positions that other Middle Eastern powers take toward the US-Iran crisis will also be crucial. And at that level, the silence of many traditional U.S. allies has been notable.

In Israel, initial official expressions of delight at Soleimani’s killing rapidly gave way to a more cautious attitude as decisionmakers pondered the fact that in any all-out clash between the United States and Iran many Israeli cities can expect to be hit very hard by the rockets and other strike forces that Lebanon’s Hizbullah has been aiming at them for 25 years. As recently as last September, the Israelis notably pulled away from engaging in any direct clash with Hizbullah, though Hizbullah hit an Israeli APC in a cross-border attack, reportedly injuring a number of IDF soldiers, after Israel had killed two Hizbullah fighters in Syria.

Saudi Arabia and the United Arab Emirates are two other significant regional players that until recently cheerled the Trump administration’s attempts to exert “maximum pressure” against Tehran. But now, they too are exercising caution– and they are actively urging it on Washington, too.

As in the wariness that Israel shows to Hizbullah, the oil-rich Arab states along the Persian/Arabian Gulf also understand their vulnerability to many different kinds of attack they could face from Iran or its allies. That lesson was brought home to them a number of times throughout 2019, most vividly in September, when Iran-linked forces, most likely acting from Iraq, inflicted massive damage on Saudi Arabia’s oil-processing facilities at Abqaiq. That attack elicited no military response from the Saudis. Instead, the kingdom quietly opened peace/truce talks with Tehran over a number of issues, including Yemen.

And even more recently, when Qasem Soleimani was traveling to Baghdad on the morning of January 3, according to Iraq’s PM Adel Abdul-Mahdi, he was carrying with him Iran’s response to a plan the Saudis had initiated to de-escalate the tensions between the United States and Iran, that he was coming to discuss with Abdel-Mahdi himself.

In these circumstances, it would seem quite unrealistic for Washington to rely on Saudi Arabia to join it at the head of any anti-Iran campaign.

Right now, the whole Middle East–and all of world politics–stand on a precipice, poised between the prospect of a war of unimaginable proportions and repercussions, and the chances of de-escalation. No-one can rule out the prospect of a war, whether through the intention of one side or the other, the miscalculation of one side or the other, or the criminal mischief-making of some other party. However, some good chances of de-escalation and war prevention remain, and there are numerous capable forces in world politics that are aiming at that goal.

It is hard to sketch out exactly what the shape of a war-averting scenario would look like. But given the tense situation prevailing in Iraq, it is almost certain that it would have to involve as speedy and orderly as possible an exit of US forces from the country, and their replacement by forces from elsewhere.

These forces should be capable of playing the technical and air-support roles in the anti-ISIS fight that the US forces played until recently; they should be politically acceptable to the Government of Iraq; and they should be deeply committed to rebuilding Iraq’s own military-technical capabilities and guarding the country’s sovereignty.

Baghdad may or may not decide to accept Russia or China in this role, though it is fairly likely that it would.

Any project of securing the exit of the US forces from Iraq and their replacement by other capable forces would need to be completed quickly, for two reasons. First, now that the Pentagon has announced the suspension of its anti-ISIS operations, the time that ISIS has to exploit the resulting security lacuna needs to be minimized. Second, so long as there is no broad political agreement among the world’s powers over how to defuse the US-Iran crisis, then, as noted, above the possibility of a massive conflagration–whether accidental or intentional– igniting and spreading uncontrollably remains unacceptably high.

All eyes, for the rest of this week, should be on the contacts among world and regional powers.