The Trump Administration's surprise decision today to pull all US troops from Syria "as quickly as possible" sent ripples far beyond the battlefield.
It was a dramatic about-face that will have long-term implications for the country, the region and international relations.
Here are some of the biggest winners and losers:
Once, Assad seemed doomed. Now, nearly eight years after the conflict started, the Syrian President will almost certainly remain in power in his tattered country.
The United States has made no secret of its distaste for the dictator, who killed and wounded hundreds of thousands of his own people, sometimes with banned chemical weapons. When evidence emerged that Assad's forces had used sarin nerve agent on civilians in a rebel-held town, US President Donald Trump authorised an airstrike that inflicted limited damage on Assad's air force. It wasn't much, but it showed some willingness to push back against the regime's worst abuses.
Now, no major powers will be playing that role. Without US troops around, Assad allies Russia and Iran will likely team up with Syrian troops to crush the rest of the rebels and opposition, handing Assad more complete control of Syria.
Just months ago, the Trump Administration said it was leaving US troops in Syria indefinitely to act as a bulwark against Iran. The US has de facto control of about a third of the country and has worked to disrupt Iranian activities.
Without the US, Iran and its ally Russia will be the most powerful foreign forces in Syria. And because they are allied with Assad, they are likely to have free rein to do what they want. In the past, Iran has used Syria as a pathway to transport troops and weapons to allies around the Middle East.
Russia has positioned itself as one of Assad's major allies. Its military has been active in Syria since 2015. Without the US troops presence, Moscow will be able to expand its role in Syria and its sphere of influence across the Middle East.
In his tweet about the withdrawal, Trump bragged that Isis (Islamic State) has been defeated, "We have defeated Isis in Syria, my only reason for being there during the Trump Presidency."
Experts say the opposite is true. There are about 15,000 Isis militants in Syria, according to best estimates. In recent months, the terrorist group has been regaining a foothold in the country.
Violent attacks have increased. (As Charles Lister of the Middle East Institute pointed out, Isis just 10 minutes before Trump's tweet claimed responsibility for an attack on Raqqa, the northern Syrian city that formerly served as its de facto capital.)
There are signs that Isis is starting to regroup. American troops "have to stay," said Ilham Ahmed, a senior official with the Self-Administration of North and East Syria, as the self-styled government of the area is called. "If they leave and there isn't a solution for Syria, it will be catastrophic," he said.
That catastrophe has come home to roost. The US withdrawal will likely lead to a rejuvenated and emboldened Isis, a terrorist threat in Syria and way beyond, too.
For months, Turkey has threatened to invade the Kurdish-controlled portion of Syria. Although the Turks have launched a handful of directed offensives, they have so far refrained from doing too much damage.
When US troops leave, that will almost certainly change. One of the major roles of US troops in Syria has been to protect the country's Kurds. They now occupy about a third of Syrian territory, which they run as if it were a semiautonomous country. A US exit will leave the ethnic minority vulnerable to attack from Turkey.
Turkish President Recep Tayyip Erdogan has all but promised just that. Days ago, Ankara threatened to launch a military offensive against Syria's Kurds. Turkey has long worried about Kurdish separatist groups, which it considers terrorists, and Erdogan has become increasingly frustrated that the Kurds have managed to take control of such a large swath of Syria, including some portions right on the Turkish border.
Israel's main mission in Syria isn't really about Syria at all: It has been working to weaken Iran. Israeli forces have launched some airstrikes. Without the US, Israel has few allies left.