Two opposing coalitions in the Middle East define a rivalry that threatens to tear the region apart. As competition for dominance intensifies, the confrontation between Iran’s network of state and non-state actors, and a counter-front of traditional Western allies – centred on Saudi Arabia, the United Arab Emirates, and Israel – has become the region’s central battle line.
Syria is at the centre of the major battle lines that cross the Middle East. A series of recent clashes in the country highlights the risk that the war there will develop into a wider regional conflagration. While Syrian President Bashar al-Assad may have established control over much of Syria, the country has become a theatre for increasingly overt confrontation between external actors.
The most visible feature of this new phase in the conflict is the intensifying confrontation between Iran – which has entrenched its forces and those of allied groups across Syria in support of Assad – and the United States and Israel, which are set on containing Tehran’s expanding influence. The Saudi role in Syria remains much more limited. Riyadh has effectively halted its attempts to topple the Syrian regime in the short term and curtailed its support for the armed opposition. Riyadh now looks to Moscow to engineer a solution that can preserve some of its interests in Syria, including by limiting Iran’s role.
The Trump administration has adopted an openly hostile position on Iran and established what appears to be a long-term, albeit limited, military presence in Kurdish-controlled areas in north-eastern Syria (where it had already deployed forces as part of the fight against the Islamic State group). The US also maintains a smaller military presence at Al-Tanf military base, on the border with Iraq in eastern Syria.
With Washington adjusting its position in Syria, Israeli forces have become increasingly active in the country. Israel fears that Iran will establish a lasting presence in Syria. To avoid this outcome, Israel has publicly laid out a series of new red lines. These include an unwillingness to accept the establishment of permanent Iranian military presence and infrastructure in Syria – not least missile-production sites – or weapons transfers to Hezbollah in Lebanon. Israel has regularly struck sites operated by the Syrian regime, Iran, and Hezbollah across Syria since 2013 – although Russia’s control of Syrian airspace has partially limited the Israeli military’s freedom of action.
Many observers of the Syrian conflict now focus their attention on the danger of military clashes between major powers with interests there. In February 2018, pro-regime forces – allegedly comprising Iranian and Russian fighters – attacked US troops stationed near the Euphrates, prompting a fierce American counteroffensive that reportedly killed around 100 fighters. A few days later, Israel intercepted an Iranian drone in its airspace, provoking an intense Israeli military response against Iranian targets in Syria and, in turn, Syria’s downing of an Israeli fighter jet. There were fears that the confrontation would escalate into a new regional conflict that drew in all these actors. While it acted to defuse the situation and impose an “iron ceiling” to contain future escalation, Russia may wish to maintain low-intensity conflict in Syria to strengthen its position.
For the moment, all parties appear unwilling to provoke all-out war. For Iran, direct conflict with another state would threaten the gains it has made in Syria. Thus, assertive Iranian operations in early 2018 seemed designed to test US and Israeli red lines, and to act as a statement in defiance of heightened anti-Iran rhetoric. An inter-state conflict would leave Israel vulnerable to a barrage of thousands of missiles – from not only Syria but also neighbouring Lebanon, given that Hezbollah, a key Iranian ally, has forces in both countries. The US, meanwhile, has shown no appetite for deep involvement in another Middle Eastern war.
Nonetheless, there will almost certainly be sustained enmity between the sides – particularly Iran and Israel – across the Syrian theatre for years to come. And there remains a severe risk that missteps by one party could quickly set off a wider conflict. For instance, were Hezbollah to launch missile strikes on Israel, the country would inevitably engage in military operations in Syria and Lebanon.
 Comments from senior Saudi official, January 2018.
 Interviews with Israeli security officials and experts, Jerusalem and Tel Aviv, February 2018.
 Anna Ahronheim, “After Years of Alleged Israeli Strikes in Syria, Will Luck Run Out?”, Jerusalem Post, 9 January 2018, available at http://www.jpost.com/Arab-Israeli-Conflict/After-years-of-alleged-Israeli-strikes-in-Syria-will-luck-run-out-533270.
 “Syria conflict: ‘Russians killed’ in US air strikes”, BBC, 13 February 2018, available at http://www.bbc.co.uk/news/world-middle-east-4305133.
 Interviews with Israeli security officials and experts in Jerusalem and Tel Aviv, February 2018, and Riyadh, March 2018.