After more than a year of relentless conflict in the Middle East, the stunning surrender of Syrian President Bashar al-Assad’s regime will go down as one of the biggest shocks in the region’s history.

In just 12 days, rebels marched from the north and then the south into the heart of Damascus, capturing the capital and ending Assad’s more than 50-year dynastic rule over the country. In less than two weeks they achieved what tens of thousands of armed opposition fighters had failed to achieve in 13 terrible years of civil war.

Moscow and Tehran, Assad’s main backers, have been unable or unwilling to stem the tide, both embroiled in their own conflicts – Russia in Ukraine, Iran and its proxies in their 14-month conflict with Israel.

In many ways, the spectacular fall of the regime appears to be one of the unintended consequences of Israel’s severe retaliation against its enemies since the Hamas attack on October 7, 2023. The following year upended all previous norms in the region and created an explosive, unpredictable environment.

Israeli forces have been carrying out air strikes on Syria for months, killing Iranian commanders and their deputies. At the same time, they are bombing facilities linked to Iran and Hezbollah, the Lebanese militant movement that also supported Assad’s regime during the civil war.

Most importantly, the rebels’ lightning offensive highlighted the precarious nature of Assad’s broken, corrupt regime.

Assad, who succeeded his father Hafez al-Assad in 2000, was a brutal despot. During the Civil War, he used the most cruel means to crush his opponents: chemical weapons, barrel bombs, siege and starvation tactics, mass arrests, torture and murder.

More than 12 million people – half the population – were forced from their homes during the decade of war. There are more than 100,000 so-called “disappeared people” – people who have been arrested by security forces and whose whereabouts are still unknown.

As the parasitic regime bled the country dry, even those from his own Alawite minority community who had sent their sons to their deaths in Assad’s war against his own people had become demoralized and hopeless after years of increasing economic and social problems.

Assad’s death will be welcomed by the many millions who suffered under his rule because he refused to compromise and negotiate with his opponents a political solution that could have stabilized the country and set it on a different path.

But the huge celebration is tempered by concern about what comes next.

The offensive was led by the strongest rebel force, Hayat Tahrir al-Sham, an Islamist group that is a former al-Qaeda affiliate and has been branded a terrorist organization by the United Nations, the United States and other countries. Its leader, Abu Mohammad al-Jolani, who has publicly expressed his desire to conquer Damascus and now appears to be the key decision-maker, once fought with the jihadist group Isis and has a $10 million bounty on his head in the United States.

In the six years since HTS has ruled the northwestern Idlib province with a civilian-led government, he has tried to rebrand the group as a more moderate Islamist movement. But it maintained control with an iron grip, and U.N. agencies have documented abuses.

If 42-year-old Jolani succeeds in realizing his claim to rule, Western powers and international agencies will be puzzled as to how to work with him and HTS.

But HTS is just one of numerous opposition groups that are remnants of the original rebellion and took part in the attack. And in the past there have been clashes between the various factions.

During the recent offensive, there was coordination between HTS and Turkish-backed factions operating under the umbrella of the Syrian National Army and other groups that surrounded Damascus from the south.

The real test, however, will come when the factions attempt to divide the spoils of victory – and power.

Malik al-Abdeh, a Syrian analyst, said he took comfort in the fact that the uprising appeared to have been clearly coordinated between HTS and the various other groups, describing the attack on the regime as a “controlled destruction plan.”

“This feeling of euphoria and pride was also tempered by the feeling that there could be violence – it’s almost too good to be true,” Abdeh said. “But it is clear that there is a plan. HTS and Jolani communicated very carefully that there was a map. That reassured a lot of people.”

Aside from the Sunni Muslim rebel groups, there are Kurdish-led forces – which the US supported in the fight against Isis – that control part of northeastern Syria.

However, Turkey sees them as an extension of the Kurdish separatists who have fought the Turkish state for decades.

Turkish troops have been stationed in northern Syria for several years to combat Kurdish militants and their ties to Sunni rebel groups. This means that Ankara is now arguably the most powerful actor in its neighboring country and will play a crucial role in the next steps.

However, Turkey has a complex and sometimes difficult relationship with HTS, which it also classifies as a terrorist organization.

The US now has around 900 soldiers in the country to support the fight against Isis.

Adding to the risk of clashes between the rebels, there are fears that Isis – which once controlled large swaths of northern and northeastern Syria – will try to exploit the chaos and stage a comeback.

Minority groups across Syria, long one of the region’s most secular countries – a factor that served Assad well as a minority – will worry about what comes next. The country has a diverse population of tribes, religions and sects.

During the offensive, Jolani, an urbane pragmatist, reached out to tribes and former enemies, brokering surrender agreements while ordering the protection of minorities.

Neighboring countries, including Israel, Jordan and Lebanon, will also be cautious, as will Gulf states that have re-engaged Assad in recent years and view Islamist movements as destabilizing forces.

Syria’s neighbors benefited from Assad’s weakening, and Israel has long wanted an end to the presence of Iran and Hezbollah on its northern border. But there are also concerns about the potential prospect of a fragile, hollowed-out state in chaos with Islamist groups at the helm.

When popular uprisings against authoritarian regimes broke out in the Middle East in 2011, a wave of optimism spread across the region. But it was all too short.

Syria descended into its devastating civil war. In Egypt, the army seized power in a popularly supported coup two years after toppling veteran President Hosni Mubarak and is ruled by one of the region’s most autocratic regimes.

Libya temporarily clashed with democracy before rival armed factions fought each other and the North African nation remains fragmented and chaotic.

The challenge facing Syria now that Assad has finally been overthrown is whether it can overcome the pitfalls and avoid the disasters that have befallen other nations after the overthrow of the despots, and whether it can endure the daunting process of reconstruction and recovery can initiate reconciliation.