– Who it supports: Washington had given moderate rebel factions fighting against government forces loyal to President Bashar al-Assad weapons and military training. It ended that aid in July in an apparent attempt to improve relations with Russia. More recently, the US has been sending weapons to Kurdish opposition forces fighting against “Islamic State” (IS) militants in northern Syria.
– Who it’s fighting against: The US has been leading an international coalition of nearly 60 countries, including Germany, targeting IS and other extremist groups with airstrikes since late 2014. It has also occasionally clashed with Syrian government forces. In April, US President Donald Trump ordered an airstrike on a Syrian airbase in what he said was a response to a government chemical weapons attack against civilians.
– What it wants: Under Trump, the US has remained steadfast in trying to destroy IS in Syria. But its intentions on other issues have become unclear. Trump told reporters in September that the US has “very little to do with Syria other than killing ISIS.” But in July, it had been deeply involved in brokering a ceasefire between government and opposition forces. The new administration has also given conflicting signals as to whether the US would oppose a peace deal keeping Assad in power. Trump’s predecessor, Barack Obama, had said that “Assad must go” for any peace deal to work.
– Which peace talks it supports: Washington has supported UN peace talks held in Geneva since 2012 between representatives from the Assad government and the Syrian opposition. But those talks, which reconvened most recently in February and March, have so far failed to reach a breakthrough. Both sides have disagreed about whether Assad’s departure should be a precondition for any final settlement.
– Who it supports: Moscow has long backed the Assad regime. It has provided government troops with air support and weapons and given it diplomatic backing at the UN and in international peace talks.
– Who it’s fighting against: Russia first intervened in Syria in October 2015 when it started airstrikes against “terrorist” targets. While Moscow has said it is targeting IS and other terrorist groups, US officials have repeatedly countered that claim by saying Russian airstrikes are primarily directed against non-IS rebel forces fighting the Assad government. The Kremlin, meanwhile, has accused the US of using its campaign against IS as a way to slow Russian and Syrian government military advances.
– What it wants: Moscow wants to keep Assad – its closest ally in the Middle East – in power and secure its military influence in the region. It has an important military airbase in the western province of Latakia and a naval base in the Syrian port city of Tartus. Russian leaders support a peace deal with broad consensus among Syria’s moderate factions that would allow Assad to remain in power. It has also hinted it may support limited autonomy for opposition forces in certain regions within Syria.
– Which peace talks it supports: While supporting the Geneva negotiations, Moscow has also sponsored talks between the Syrian government and the opposition in Astana, Kazakhstan that began in January 2017. In October, Russian President Vladimir Putin said Russia would host another set of talks focused on a new Syrian constitution in the southern Russian city of Sochi on November 18.
– Who it supports: Turkey has fought alongside non-Kurdish factions in the Syrian opposition including the Free Syrian Army (FSA).
– Who it’s fighting against: Ankara conducted airstrikes against IS targets as part of the US-led coalition. It has also carried out unilateral airstrikes against Kurdish opposition forces in northern Syria and sent ground forces into Syria to fight IS and Kurdish forces as part of the Turkish-led operation known as “Euphrates Shield.”
– What it wants: Ankara wants to suppress Syria’s Kurds to ensure that Turkey’s own Kurdish population is not inspired to rebel against Turkish authority. It also wants to defeat IS and other extremist groups that have committed terrorist attacks on Turkish soil. Recently, Turkish leaders have been ambivalent on whether Assad should be allowed to stay in power in a final peace deal.
– Which peace talks it supports: Turkey has been heavily involved in the Geneva talks and has co-sponsored the Astana negotiations. It criticized Russia’s proposed Sochi talks after Moscow invited representatives from the Kurdish opposition.
– Who it supports: Tehran has supported the Assad government since at least 2012, giving the regime extensive military aid in the form of training, weapons and intelligence sharing.
– Who it’s fighting against: By siding with Assad, Iran has directly and indirectly been fighting against both moderate and extremist factions in the Syrian opposition. Members of Iran’s elite military force, the Iranian Revolutionary Guard Corps (IRGC), have reportedly taken part in Syrian government offensives.
– What it wants: Apart from Syria, Iran has few friends in the Middle East. Propping up Assad ensures an ally against Iran’s regional rivals, Israel and Saudi Arabia. Tehran also needs Syria to transport weapons to Hezbollah, which also opposes Israel, in neighboring Lebanon.
– Which peace talks it supports: Iran joined the Geneva peace talks in November 2015 after the US dropped its longstanding opposition to Iranian involvement. Tehran has also sponsored the Astana peace talks along with Turkey and Russia.