Syrians seeking to chart their own political course, free from outside interference, following the ouster of President Bashar al-Assad may be thwarted by the geopolitical ambitions of their neighbours, who already have a foothold in the country, experts say.

"We all want this to be a moment of liberation and self-determination," for the Syrians, said Mostafa Minawi, an associate professor of history at Cornell University. 

But, with all the external players already involved in Syria, "I don't know how that would happen." he said.

"They are not planning on going anywhere."

Those players include Turkey, which has an ongoing interest in Syria because of its Kurdish minority; Iran, which, along with Russia, had supported the Assad regime; and Israel, which has occupied Syria's Golan Heights and expressed concerns over Islamist rebels.

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Turkey

Observers expect Turkey to play a dominant role in Syria's future, having established a significant military foothold in a northern strip of the country, controlling territories such as the city of Afrin and parts of the countryside outside Aleppo.

These areas serve as buffers against Kurdish groups and provide leverage over Syria's political landscape, analysts say.

"While Turkey may advocate for a decentralized or restructured Syria, it is unlikely to completely withdraw its influence, as its strategic interests remain deeply tied to Syria's future," Sajjan M. Gohel, international security director at the Asia-Pacific Foundation in London, said in an email to CBC News.

Turkey's main concern are Syria's Kurdish forces, which it considers to be an extension of the Turkey-based separatist Kurdistan Workers' Party (KWP), which seeks Kurdish self-rule. The Turkish government has labelled the KWP a terrorist group and doesn't believe Kurdish forces in Syria should have any presence.

The U.S. partnered with those Kurdish forces to rout the Islamic State group. But this alliance has been a source of tension between Washington and Ankara, even though both are NATO allies.

Turkey is "very much on the ground," Minawi said. "They're not going anywhere because there are Kurdish groups along the northern border of Syria that they will not allow to develop their own autonomous region because this threatens Turkey's own autonomy."

Ankara has the strongest channels of communication, and history of working, with Hayat Tahrir al-Sham (HTS), the Islamist rebel alliance that now controls much of Syria, positioning it to reap the benefits of the Assad regime's demise, Gonul Tol, director of the Middle East Institute's Turkish Program, wrote in Foreign Affairs.

"Turkey will certainly have a role to play. Its support for the groups in charge, the long border it shares with Syria, and its military presence in the country give it significant influence," he wrote.

Iran and Russia

The defeat of Assad, who was backed by the Iranian government, is a significant blow to Tehran, which has already suffered strategic losses after Israel pounded its allies Hamas and Hezbollah, in Gaza and Lebanon respectively.

"Syria represented a springboard for the Iranian regime to project its influence as far as the Mediterranean, and that has disappeared," Jonathan Piron, a historian and Iran specialist at the Etopia research centre in Brussels, told France 24.

"Iran finds itself in an unprecedented position of weakness."

However, its long-standing support for Assad and its deployment of Syrian Shia militias have entrenched sectarian divisions in the country,  meaning Iran can also be expected to maintain some kind of presence, Gohel said.

"Even with reduced Iranian support without Assad being in Syria, the militias may remain influential, potentially undermining efforts for national unity," he said.

Minawi agrees that he could not imagine Iran fully disengaging.

"They even already stated that they are ready to talk with the interim government, but they are very much on the retreat."

Still, Foad Izadi, a professor at the University of Tehran, told the Wall Street Journal that Iran has historically found a foothold in fractured states, and might be able to maintain some influence in Syria, regardless of the country's political future.

"A democratic Syrian government is not going to be friendly to Israel, it will be supportive of the Palestinian cause," which is backed by both Iranian-supported Hamas and Hezbollah, he said.

 And if you're going to have chaos, and Syria turns into another Libya, that's also something Iran can manage."

Meanwhile, although not a regional neighbour, Russia had played a critical role in supporting Assad's regime, providing military and diplomatic support.

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Russia may seek to retain leverage through agreements on military bases, thereby ensuring a long-term footprint in Syria, Gohel says. 

"The West will want that to end and may be willing to legitimize whatever regime replaces Assad, even recognizing the terrorist group HTS … if it means reducing Iran and Russia's presence," he said.

Israel

Since the fall of the Assad regime, Israel has carried out heavy airstrikes across Syria. Meanwhile its troops advanced into a roughly 400-square kilometre buffer zone inside its neighbour, which was established by the UN after the 1973 Mideast war. 

The airstrikes, the Israeli military said, took out Syrian missiles, drones, fighter jets, attack helicopters, tanks, radar systems and the country's small naval fleet.

They "basically crippled any military capability and infrastructure," Minawi said. "It's a way of defanging the state before the state even gets off."

Moving into the buffer zone is prohibited by the UN agreement, and brought some international condemnation. But Israeli political and military leaders say the move is temporary and not a prelude to further entering Syrian territory.

Israel says its immediate goal is to prevent the instability in Syria from spreading. The troops will remain "until security on our border can be guaranteed," said Prime Minister Benjamin Netanyahu.

Israel is also using the political vacuum to shore up its defensive positions. Israel has supported some rebel groups in southern Syria as part of a strategy to maintain a buffer zone and prevent hostile forces from operating near the Golan Heights, Gohel said.

"This may continue. For Israel, the other priority will be to ensure Syria is not used as a cog to aid Hezbollah."

Avi Dichter, an Israeli minister and member of the security cabinet, says the goal "is to establish facts on the ground," the Washington Post reported.

Though HTS and other Sunni opposition groups fought for years against Iranian-backed forces, Dichter said Israel is still "preparing for the possibility that the rebels reach an agreement with Iran, with Hezbollah."

Israel needs "to first see how [the rebels] build their state and their army," Dichter said, according to the Post.